Rail Engineer - Issue 185 - July/August 2020

by rail engineers for rail engineers

JULY/AUGUST 2020 – ISSUE 185

SLAB TRACK

for HS2 ELECTRIFICATION AND THE ENVIRONMENTAL CHALLENGE

The history and future of electrification, and how it is essential if the railway is to meet its zero-carbon goals.

A DOCKLANDS UPDATE

THE TRAIN NOW ARRIVING…

The DLR opened in 1987. Extended several times since, it now needs a major signalling and control upgrade.

HS2’s huge Old Oak Common interchange station will link with the Elizabeth line, Heathrow Express and the Great Western.

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28 CONTENTS

40

06|

News

12|

Why electrification is the key to keeping the UK’s climate progress on track

14|

Slab track for HS2

3

August Bank Holiday, HS2, FOAK, Tyne & Wear Metro, Railtex/Infrarail, CP6, Bletchley.

OPINION: Garry Keenor and Paul Hooper of Atkins argue the case for more electrification.

David Shirres suggests why HS2 has gone for ballastless track, and what form it will take.

20

20|

Slab Track Paving the P-Way

The UK already has ballastless track in some locations, often fitted by Rhomberg Sersa.

42

28|

The train now arriving…

36|

A Docklands update

40|

Eyes on the network

50|

Unlocking Innovation: the Digital Railway

42|

Electrification and the environmental challenge

58|

Beeching reversed: reopening the Northumberland line

46|

Re-engineering rail freight

62|

Cleaning the rail head

Bob Wright looks at plans for HS2’s huge Old Oak Common interchange station.

The DLR opened in 1987. Extended several times since, it now needs a major signalling upgrade.

TFT displays from Relec keep passengers informed, entertained and safe.

Peter Stanton discusses the history and the future with electrification expert Peter Dearman.

Rail Operations Group’s Class 93 is planned to be the UK’s first tri-mode locomotive.

Undeterred by Covid restrictions, RIA staged a fascinating technical conference over five days.

Mark Phillips considers plans to reopen a line closed to passengers in 1964.

Malcolm Dobell looks at various ways of removing those troublesome leaves from the line.

Rail Engineer | Issue 185 | July/August 2020

2 Great Shows

1 Exciting Rail Event

Book Your Stand Now

Joining forces to shape the future of UK rail In 2021 Railtex will play host to Infrarail.

The UK’s most important events in the rail calendar will come together to form the ultimate show for the rail industry.

To be part of the most comprehensive rail exhibition of 2021 contact the team on +44 (0)1727 814 400 or via email uk-railhub@mackbrooks.co.uk

11-13 May 2021 NEC, Birmingham www.uk-railhub.com

15th International Exhibition of Railway Equipment, Systems & Services

13th International Railway Infrastructure Exhibition

RAIL ENGINEER MAGAZINE

EDITORIAL

Follow the Science Use of mainline rail passenger services and cars is now respectively 18 and 85 per cent that of last year. With the Covid crisis accelerating trends of flexible and home working and encouraging travellers into the isolation of their cars, it will be a long time before rail ridership returns to previous levels.

This presents a huge financial challenge which could make it difficult to justify rail capacity investment. To do so, the railway needs to play to its strengths in reducing transport carbon. This needs urgent action if the 2050 target of net-zero carbon is to be achieved.

Although rail is well known to be an environmentally friendly form of transport, decision makers do not seem to understand the science that makes rail the easiest sector to decarbonise and the only one that can offer net-zero carbon high-speed passenger and heavy freight haulage.

As an example, when launching the Jet Zero Council, Boris Johnson hoped it would pave the way for zero-emission long-haul passenger flights. Last year, Grant Shapps wished for an electric revolution in the skies. However, exuding enthusiasm to get things done does not change the laws of physics. A long-haul plane takes off with, typically, 100 tonnes of jet fuel on board. If an electric plane was to store this amount of energy, its battery would weigh a few thousand tonnes and be about ten times the size of a jet plane’s fuel tank.

This explains why the chairman of the government’s environmental advisory body, the Committee for Climate Change (CCC), has advised Shapps that “zero-carbon aviation is highly unlikely to be feasible by 2050”.

Unfortunately, this is not the only CCC advice that has gone unheeded. Its impressive net-zero report provided a comprehensive zero-carbon blueprint for each sector. Yet there is little, if any, action on its key recommendations which include removing gas boilers from the nation’s homes, large scale carbon capture and storage, a massive increase in hydrogen production, doubling electricity generation and grid capacity with a threefold increase in renewable power.

Net-zero will only be achieved if the nation’s transport can be weaned off the 55 million tonnes of petroleum it uses each year.

Electricity, which can be zero-carbon, depending on how it is generated, is the only other way of transporting such huge amounts of energy. However, when used for road transport, electricity needs to be stored. Yet, as shown above, batteries store much less energy than fuel tanks.

This need not be a constraint for rail transport, which has a unique ability to use electricity as it is generated. With the ability to suck up megawatts of power on the move, electric trains offer high-powered, high-efficiency, zero-carbon transport, with many other benefits. The

industry needs to ensure that government understands the science that gives railways this exceptional advantage.

Electrification’s advantages are further explained in two of this month’s features. One by Garry Keenor and Paul Hooper of Atkins also highlights the high cost and lost skills from the historic boom and bust approach to electrification. Peter Stanton’s article explains the ‘route rationalisation, resignal and electrify’ philosophy and stresses the need for effective production management to ensure cost effective delivery, which is essential if government are to invest in electrification.

An interesting decarbonisation initiative is the Class 93 locomotive being developed by the Rail Operations Group (ROG) and Stadler to provide more electrically powered freight trains. Our feature explains that this is just one of the ROG’s various freight initiatives. Another worthwhile project is finding solutions to the problem of low rail adhesion, as described by Malcolm Dobell who explains why adding water to slippery rails might be a good idea.

The carbon savings that would stem from a five per cent passenger modal shift from road to rail would save more carbon than rail’s current emissions. However, this would require a 50 per cent increase in rail capacity. This is one of the reasons why HS2 is needed. The amount of traffic that it will carry is illustrated by Bob Wright’s feature on the massive new interchange station at Old Oak Common. We also explain why HS2’s project’s first railway systems contract is for pre-cast slab track. Rhomberg Sersa has been laying such track for years, as we explain in a back-to-basics feature about both ballasted and ballastless track. The new line to Ashington will be a much smaller new passenger railway. As Mark Phillips describes, this reverses a Beeching cut to provide much-needed connectivity benefits.

The Docklands Light Railway is not quite so new. Between 1987 and 2011, it has steadily expanded to provide the connectivity to develop the area it serves. We describe why its original digital signalling needs to be replaced.

On the mainline railway, installing digital signalling has taken longer than expected. This topic was recently considered at a week-long digital signalling webinar staged by the Railway Industry Association.

Clive Kessell’s report of this event explains the complexity of the ERTMS programme and considers what is different now.

Finally, Nigel Wordsworth reports that a combined Railtex and Infrarail is to return on 11 - 13 May. We look forward to seeing you DAVID there.

SHIRRES

RAIL ENGINEER EDITOR

Rail Engineer | Issue 185 | July/August 2020

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THE TEAM

NEWS

Editor David Shirres david.shirres@railengineer.co.uk

Production Editor Nigel Wordsworth nigel.wordsworth@railengineer.co.uk

Production and design Adam O’Connor adam@rail-media.com Matthew Stokes matt@rail-media.com

Engineering writers bob.wright@railengineer.co.uk clive.kessell@railengineer.co.uk collin.carr@railengineer.co.uk david.bickell@railengineer.co.uk graeme.bickerdike@railengineer.co.uk grahame.taylor@railengineer.co.uk lesley.brown@railengineer.co.uk malcolm.dobell@railengineer.co.uk mark.phillips@railengineer.co.uk

Network Rail to deliver 520 projects over August bank holiday

paul.darlington@railengineer.co.uk peter.stanton@railengineer.co.uk stuart.marsh@railengineer.co.uk

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Rail Engineer | Issue 185 | July/August 2020

Network Rail will be carrying out 520 renewals projects worth £105 million over August Bank Holiday Andrew Haines, Network Rail chief executive, said: “Throughout this pandemic, we’ve continued to work on the railway to make it more reliable and to improve journeys for passengers. This August Bank Holiday is no different, as we invest over £100 million to upgrade the railway.”

The major projects to be carried out over the August Bank Holiday weekend include: » Significant track replacement work in the Coventry area that will make journeys more reliable on the West Coast main line. A reduced timetable will be in place over the bank holiday weekend, with no direct services running between Birmingham and London Euston. Replacement bus services will be in operation. » Moving signalling control from Ditton to the state-of-the-art Manchester Rail Operating Centre between 29-31 August. This will make the railway more reliable for passengers, enabling signallers to rapidly respond to disruption and route trains faster, therefore reducing delays. During this work, trains will be diverted onto different routes to keep services running in and out of Liverpool, and some rail replacement buses will operate between Warrington-Runcorn and Crewe-Liverpool South Parkway. » Switches and crossings renewals, signalling commissioning and plain line track renewals in St Pancras area that will improve safety of the tracks and work towards the opening of Brent Cross station. This will affect EMR and Thameslink services on 29-31 August, and will see a significantly reduced service between St Pancras and London Bridge. » Major project works taking place at King’s Cross for the King’s Cross remodelling project, which will increase capacity and improve reliability on the East Coast Main Line. There will be no train service in operation to/from London King’s Cross before 07:10 on 30 August as a result of this work. » Switches and crossings renewals and heavy maintenance works at Clapton to improve track reliability. Will affect London Overground, Stansted Express and Greater Anglia on 30 August. » Bridge replacement works in Catford that will safeguard the future of the railway lines between Hayes and Lewisham, and Nunhead to Shortlands. Both of these lines will be closed while the works take place.

NEWS

HS2 vent shaft headhouse at Chalfont St Peter designed to fit into landscape HS2 has published its final design for the Chalfont St Peter vent shaft headhouse - the first of four similar structures that will provide ventilation and emergency access to the high-speed rail line's 10-mile-long Chiltern tunnel.

Set back from the road, the design of the single-story building takes its inspiration from the style of local barns and other agricultural buildings, allowing it to fit into the surrounding landscape.

The building will be wrapped in a simple grey zinc roof with doors and vent openings picked out in a dark bronze colour to provide contrast. The preweathered grey zinc roof will age naturally over time, without loss of robustness or quality, while the whole structure will sit on a simple dark blue brick base.

Below ground level, a 60 metre ventilation shaft will reach down to the twin tunnels below, with fans and other equipment designed to regulate air quality and temperature in the tunnels, remove smoke in the event of a fire and provide access for the emergency services.

Mature trees along the existing boundary are being retained as far as possible and, once construction is complete, the whole site will be landscaped with new trees and hedgerows planted to help screen the site from neighbouring properties.

The overall scale and visual impact of the building has also been significantly reduced.

Bird boxes, reptile basking banks, a grass snake laying heap and a hibernaculum will also be created to encourage wildlife to return. Material excavated from the shaft will be used to

create much of the landscaping and avoid putting extra lorries onto local roads.

The plans have been drawn up by HS2’s main works contractor Align JV – a team made up of Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick - working with its design partners Jacobs and Ingerop-Rendel, architect Grimshaw and landscape designers LDA. Rohan Perin, HS2’s C1 project client director, said: “HS2 remains committed to work proactively with residents, wider community and our stakeholders to be a good neighbour during the build phase.

“Once construction is complete, the headhouse at Chalfont St Peter will be one of very few structures of the Chiltern tunnels that will be visible to residents living nearby.

That’s why it’s critical that we get the design right.”

Rail Engineer | Issue 185 | July/August 2020

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NEWS

Network Rail supports First of a Kind innovators A total of 11 out of the government's £9.4 million First of a Kind (FOAK) 2020 competition to provide a better, more reliable and efficient railway for passengers and freight users are being supported by Network Rail.

Funded by the Department for Transport and managed by Innovate UK, the competition encourages innovation in the rail industry by asking companies for ambitious ideas that could transform the railway. The projects that will directly support Network Rail’s Research & Development (R&D) Portfolio include: » Demonstrating low cost 10Gigabit+ connectivity for the railway » Creating a novel and cost-effective composite footbridge for use on the railway » Improving resilience through a surface water flooding decision support system » Tunnel and station monitoring using railway optical detection to identify obstructions » Integrated optical fibre sensing to optimise rail

switches & crossings maintenance.

In addition to the FOAK 2020 competition, Network Rail continues its partnership with Innovate UK to run competitions using the Small Business Research Initiative (SBRI) approach – where innovators compete for a share of funding to solve a certain challenge.

Winners of the competitions that have been delivered so far proposed a number of solutions to address: » Developing detection technology on the ends and edges of platforms to detect and reduce trespass on the railway » Automating data processing for railway structure gauging – a process that ensures a safe distance exists between trains and structures such as tunnels » Automating tunnel

Rail Engineer | Issue 185 | July/August 2020

examinations and undertaking security surveillance and analytics to reduce the need for workers to monitor the network and test asset condition manually.

The competitions generated from the combined partnerships between Network Rail, Department for Transport and Innovate UK in the last year have collectively been worth over £15 million, with each initiative providing opportunities for smaller organisations to work with Network Rail to bring innovative technology into the railway. This is enabled through the support from Innovate UK and the Knowledge Transfer Network.

Kelvin Davies, innovation lead for rail at Innovate UK, highlighted: “As the UK’s innovation agency we are here to support the best ideas

from the UK’s most innovative companies. Through working with Network Rail, we have seen the strength of interest, quality of applications and enthusiasm. This shows there is a real confidence that businesses large and small can grow by focussing on opportunities in rail. This is vital as we all work together to build a bigger, better and greener railway”.

These initiatives form part of Network Rail’s R&D portfolio for CP6 and will help drive improvements in efficiency and safety in the rail industry through new technology. The partnership with Innovate UK and the competition opportunities also fit with Network Rail’s desire to be easier to engage and work with as part of the Open for Business programme.

NEWS

New Tyne & Wear Metro depot at Howdon Tyne and Wear Metro's new train depot at Howdon is close to completion. Set to officially open this summer, the former landfill site has been transformed.

New tracks and overhead lines are in place and a new maintenance shed has been built and fitted out along with new facilities for staff.

Howdon will be used for the cleaning and preparation of up to a quarter of the Metro fleet while the main Metro depot at Gosforth in Newcastle is completely rebuilt in a £70 million project set to begin this summer and to take five years.

The development has been funded as part of the £362 million Metro fleet replacement project.

Project manager, Tabitha Callaghan, said: “We are now close to the completion of the Howdon Metro depot.

“The site will be vital for the future of Metro because there won’t be enough space for all of the trains when work starts on the main depot rebuilding project at Gosforth.

“Howdon gives us the capacity to stable

up to one quarter of the Metro train fleet there and carry out light maintenance work at that location.

“There are new facilities for Metro drivers and maintenance staff who in the future will need to book on for duty at Howdon.”

Buckingham Group Contracting Ltd is building the temporary Metro depot on behalf of Nexus.

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Rail Engineer | Issue 185 | July/August 2020

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NEWS

'Ultimate rail event' Railtex/Infrarail to return next year for co-located event Following a challenging and unprecedented period brought on by the COVID-19 pandemic, the rail industry is now targeting a slow but determined recovery. Successful rail events will play a major role in kickstarting business activity and reconnecting the key decision makers with their peers.

International events organiser Mack Brooks Exhibitions has announced the news that Railtex and Infrarail, which have both served the rail market for over 20 years, will return in 2021 and come together to form what is being billed as the ‘ultimate show for the UK rail industry’.

The NEC Birmingham will play host to the all-encompassing event, which is expected to welcome more than 400 exhibiting companies and thousands of visitors across three days of networking, education and showcasing. Railtex/Infrarail 2021 will take place 11 -13 May, with the organisers encouraging businesses to get involved during a period that could well shape the future of UK rail.

New partnerships, new opportunities The inaugural, co-located Railtex/Infrarail exhibition will offer a brand-new programme of activity, held in partnership with supporting organisations old and new. An agreement has been struck with the Railway Industry Association (RIA), which will host a varied selection of conferences throughout the three days.

A new feature from RIA, supported by Network Rail and other stakeholders, is the Unlocking Innovation (UI) Zone, which will be a daily programme focusing on new ideas and thinking that could benefit the railway, its passengers and the economy. There will also be a new UI Showcase stand, where discussions can be held with presenters from important organisations such as Network Rail, RIDC, Tier 1, HS2, regional authorities, UKRRIN and Innovate UK. Also organised by RIA will be the returning Future Focus Conference. A three-day free to attend, high level, strategic conference covering topics for the whole industry supply chain with political and industry leaders presenting on UK rail’s strategic direction. A Meet the Buyer/Commercial Officer programme will also offer the opportunity for pre-booked meeting slots with a range of UK and overseas rail buyers.

More products, services and live demonstrations than ever By combining Railtex, the premier exhibition of railway equipment, systems and services and Infrarail, the leading showcase for every aspect of railway infrastructure technology and expertise, next year’s event will be the perfect platform for companies covering every aspect of the railway industry and its associated disciplines.

Never before has there been an opportunity to see so many different products, services and innovations under one roof at a UK rail exhibition as there will be at Railtex/Infrarail 2021. From track, rolling stock, and infrastructure to plant, machinery and civil engineering, there will be something for everyone involved in rail in any capacity. Exhibitors will be able to grab the attention of attendees by hosting their own live demonstration of their products, either at their stand or at the dedicated track display area. There is no better way to promote your brand’s capabilities than with a live demonstration, and the NEC will provide the perfect setting next May. Rail Engineer will be there as usual, hosting a seminar theatre that will give exhibitors the chance to present their technology and introduce their latest products to a wide-ranging audience.

High level addresses from the industry’s leaders In previous years, Infrarail and Railtex have always hosted influential keynote speakers from senior figures and next year will be no exception.

Keynote speeches from figures such as the Rail Minister Andrew Jones MP, chief executive of RIA Darren Caplan as well as the then managing director of Digital Railway (Network Rail) Stuart Calvert were included in Railtex’s previous comprehensive conference programme.

Infrarail has played host to former State Secretary of Transport Chris Grayling and former HS2 managing director Paul Griffiths, as well as Network Rail’s former Digital Railway MD, David Waboso CBE. While next year’s programme is still to be confirmed, there is promise of a range of high-profile speakers from all aspects of UK rail.

Stand bookings are now open Stand bookings are now being taken and potential exhibitors are urged to take action to avoid disappointment. Natig Asadullaev, exhibition manager for Railtex/Infrarail 2021, said: “Following the postponement of 2020’s exhibitions, we are already anticipating a huge response to bookings for next year’s event.

“I have no doubt that Railtex/Infrarail 2021 will be the highlight of the rail industry calendar year and for both tier one and two companies and SMEs, there is no better place to be seen and to take part in the shaping of the future of the UK rail network.”

Rail Engineer | Issue 185 | July/August 2020

NEWS

Network Rail "making a good start" to CP6, says ORR

Rail Regulator the Office of Rail and Road (ORR) has published its 2019-20 annual assessment of Network Rail and has found that the infrastructure owner beat its target for efficiency savings last year.

In the first year of the new control period 6 (CP6), Network Rail saved more than £385 million as it looks to deliver £3.5 billion of efficiency savings over the five-year period.

However, ORR claims that this followed its early intervention in holding Network Rail to account and to improve planning after concerns were raised that Network Rail might not deliver

the required volumes of work and efficiency improvements needed in CP6.

Passenger and freight performance also varied by region over the last year, with opportunities for Network Rail to learn from its better performing regions to improve performance nationwide. For example, passenger train performance has been good in the company’s

Southern and Wales & Western regions, but below target in others, with poorest performance in the North West & Central region.

Freight performance was below target in three of the company’s five regions. ORR has separately investigated and reported on poor train performance in the North West & Central region and confirmed that Network

Rail has now developed suitable improvement plans.

The company made progress in developing longer-term plans to improve performance; for example, improving the skills of operational staff. It also delivered its planned works to renew the railway in 2019-20. This is a good start to its five-year plan for keeping the rail network in good condition.

Three huge cranes remove flyover at Bletchley Network Rail has been using three of the largest cranes in the UK to lift out sections of 'Bletchley flyover', which was built in the early 1960s to allow trains travelling from West to East to cross over the West Coast main line.

Work has been underway since April to remove concrete spans so the structure can be rebuilt to modern standards

as part of the East West Rail project, which is building the first direct rail link between Oxford, Bedford, Milton

Keynes and Aylesbury in more than 50 years.

To remove the sections above Buckingham Road, the main route in and out of Bletchley, one of the cranes has been installed on Buckingham Road itself, closing it to traffic from 5 July to August 30.

Pedestrian access will be maintained by a protected walkway so people can still cross Buckingham Road despite the work. However, even this will not be available at certain times so, when the walkway is closed, a shuttle bus, running every 15 minutes,

will take people between the train station and bus station.

Tim Shoveller, managing director for Network Rail’s North West and Central region, said: “The work to remove Bletchley flyover as part of the East West Rail project is a hugely impressive feat of engineering. East West Rail will transform connectivity and journey times across the heart of the country. The resulting low-carbon transport system will bring huge benefits to passengers and businesses - driving economic growth and creating opportunities for housing and new jobs.”

Rail Engineer | Issue 185 | July/August 2020

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OPINION

WhyTOrail electrification is key KEEPING THE UK’S CLIMATE PROGRESS ON TRACK GARRY KEENOR

PAUL HOOPER

L

ast year the UK was the first major economy to legally commit to becoming ‘carbon-neutral’ by 2050. The Department for Transport’s (DfT) vision is to remove diesel-only traction from our railways by 2040.

How can we speed up rail electrification and create a greener transport network fit for a carbon-neutral economy?

Railway electrification began in the early 1900s, but, even considering schemes currently under construction, only 46.5 per cent of our railway is electrified, with the majority of the rail network operating with diesel trains. To achieve net zero carbon, we need to electrify more of the railway in the next three decades than has been achieved in the last six.

Fossil fuels have seeped into almost every part of our economy, and the railways are no exception. For the electrified routes, we must also ensure that the energy required to power our transport is green and from low/zero carbon sources. We will not have met our goal while electric vehicles and railway electrification use energy from gas and other high carbon generation sources.

Stopping the stop-start habit Countries like Germany have steadily electrified their networks, year after year, in a rolling programme of works. Yet the UK has witnessed periods of intensive electrification, invariably followed by an abrupt halt - slowing down the process and leading to cost inefficiencies and reluctance to restart the programme.

This cyclical process, known as ‘boom and bust’, has also led to a talent drain; during lengthy spells of stasis, our best practitioners either find work elsewhere or leave the industry entirely, with vital skills being lost. This has been seen in the current dip since the

Rail Engineer | Issue 185 | July/August 2020

electrification programme was halted in 2017, with design volumes down significantly and construction volumes reducing.

Looking to the long-term A long-term approach will help avoid the problems of ‘boom and bust’ and maintain steady progress, reduce unit costs, manage expectations and prevent mistakes from rushed processes. It also permits electrification of routes to be integrated with rolling stock replacement and modernisation programmes, including remodelling and resignalling.

Electrification should be seen as part of a wider package of railway improvements, since it is not possible to complete electrification without renewal of other elements.

An electrification programme brings together many different suppliers, consultants, managers, and stakeholders - all with aspirations and concerns. Establishing longterm partnerships with suppliers can create mutually beneficial relationships, incentivising the supply chain and expediting the process.

OPINION

One goal, many skills Electrification is a complex process, demanding different skills, from earthing and bonding to electromagnetic compatibility. We must command teams with the right mix of talents and expertise and draw on digital resources.

Our railways are a patchwork of overlapping designs, built at different times and with their own challenges. Digital tools allow us to develop OLE (overhead line equipment) layouts more quickly, with a higher level of consistency, and deliver standardised digital outputs for use by procurement, construction and maintenance teams.

One tool, Polecat, has been successfully deployed on over 3000 STKs (single track kilometres), delivering 25-40 per cent reductions in production times for OLE design drawings.

Another tool, D-RSS, has huge potential to challenge conservatism in traditional OLE design rules. It was recently used to justify running through Steventon bridge on the Great Western main line at 110mph (issue 182, March 2020), almost three times the speed permitted by the current OLE standards.

The future’s electric The last few decades have shown how complex the electrification process is. It is vital to combine long-term thinking with a holistic approach to railway electrification. As an industry, we must become more efficient, reduce unit costs, and collaborate to implement electrification and keep the UK’s progress to a carbon-free economy on track.

A greener economy is becoming the bedrock of our national policy. Unless we drastically curb our emissions, we’ll face adverse consequences of pollution, degradation and climate change within the next generation - we must act now.

Garry Keenor is group engineer (electrification) & technical authority for mechanical OLE systems at Atkins Paul Hooper is technical director and professional head of discipline for electrification at Atkins

Rail Engineer | Issue 185 | July/August 2020

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INFRASTRUCTURE

DAVID SHIRRES

SLAB TRACK

for HS2 E

arly railway track carried trains running at 50km/h (30mph) with three-tonne axle loads. Over almost 200 years, ballasted track has been developed to the point where it can carry heavy freight trains, with axle loads of 25 tonnes or more, or high-speed passenger trains at over 300km/h (186mph). Ballasted track is relatively cheap and allows track adjustments as required.

However, this advantage becomes a weakness for high-speed operation, which has demanding tolerances and high dynamic loads. In such an environment, ballasted track is at its technical and economic limits.

RAIL.ONE's Rheda 2000® in-situ cast slab track being installed in Bowshanks tunnel in 2014 for the new Borders Railway.

After the introduction of the world’s first dedicated high-speed line in Japan in 1964, it became apparent that significant effort was required to maintain track geometry. In 1972, Japanese National Railways installed a trial 12-kilometre length of ballastless track on its Shinkansen network, to consider alternatives.

Since then, high-speed lines in Japan have generally used slab track, although European high-speed railways were not to take this decision until much later.

1972 also saw a trial 700-metre section of slab track, formed of sleepers cast into a concrete base, laid on an embankment in Germany.

This was the first use of the now widely used Rheda system, which is named after the station where it was first installed. Prior to that, slab track was generally used in tunnels, due to

Rail Engineer | Issue 185 | July/August 2020

concerns about settlement on embankments, deformation under load and thermal expansion on bridges.

The development of pre-cast slab systems, which offered construction benefits and reduced transmission of vibrations, started in the late 1970s when the Bögl system was first tested in Germany. Shortly afterwards, the ÖBB/ Porr system was developed, in association with Austrian railways. The 1990s saw the introduction of these systems and significant development work on other ballastless trackforms.

In 1994, after maintenance issues with ballasted track on its early high-speed lines, Deutsche Bahn decided that slab track had to be considered for new high-speed and upgraded lines in Germany. This drove slab track

INFRASTRUCTURE

Despite its increasing use and proven benefits, ballastless track is significantly more expensive to install than conventional track. The 2014 EU research publication “Design requirements and improved guidelines for track” (available online) indicates that the construction cost of slab track can be over twice that of ballasted track.

When taking the decision about its track, or indeed any railway system, HS2 has had the opportunity to consider the extensive worldwide experience of high-speed railways throughout the world. For example, Chinese railways have many thousands of kilometres of high-speed slab track, although they do not have the long-term operational experience of ballastless track that countries such as Germany have.

A review of trackforms around the world studied the use of ballasted track on highspeed lines, which include HS1 and the Paris to Strasbourg line, phase 2 of which opened in 2017. These lines carry 14 and 11 million gross tonnes per annum (MGTPA) respectively.

When HS2 phase 2 is operational, its London to Birmingham section will have up to 18 trains an hour, running at a predominant normal operating speed of 330km/h (205mph), and will carry over 60 MGTPA. This will make it one of the world’s most heavily loaded high-speed lines. Any laterunning trains will run at HS2’s maximum speed of 360km/h (225mph) to recover the timetable.

HS2’s assessment of the feasibility of maintaining ballasted track, when used by trains running at this speed, concluded that cumulative tonnage was the key factor in the deterioration of the track system and therefore determined the amount of tamping required.

As the life span of the ballast is a function of the number of tamps, higher tonnages require more renewals.

As a result, for HS2’s operating conditions, ballast life is likely to be around 20 years. The requirement to renew all of HS2’s track at this rate would be extremely costly, cause significant disruption and require temporary speed restrictions. Even with improved dynamic track stabilisation, hand back at over 300km/h (186 mph) is not considered feasible.

PHOTO: ISTOCKPHOTO.COM

A big decision

PHOTO: ISTOCKPHOTO.COM

development and, perhaps, paved the way for China’s high-speed rail boom. After opening its first high speed line in 2008, by 2018 China had a built a 29,000-kilometre high-speed rail network with over 19,000 kilometres of slab track.

Rail Engineer | Issue 185 | July/August 2020

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INFRASTRUCTURE Other benefits

PHOTO: HULLIE

The track is part of a complex system with multiple interactions, particularly in respect of earthworks and structures.

HS2’s earthworks and ground improvement measures have to provide a stable base for whatever trackform is chosen. Their design needs to take account of geology, inherent properties of existing ground and geodynamics that might cause Rayleigh waves as well as earthworks to bridge transitions. From an

overall system design perspective, slab track offers the benefits of shallow construction depth and reduced dead load. A further advantage is that hardspots are less of an issue, due to the inherently stiffer structure of slab track. With ballasted track, the transition between earthworks and structures can be problematic.

A potential issue is that slab track can be more prone to groundbourne sounds and vibrations (GBSV) than ballasted track. Extensive research has been undertaken on this issue to derive track specifications that ensure GBSV is within acceptable limits - slab track systems have specific features that address this issue.

However, GBSV can be a particular problem in tunnels, especially for buildings above them.

For this reason, HS2’s urban track installation contract, which includes all tunnels in urban areas, specifies in-situ cast track designed to minimise GBSV.

Rail Engineer | Issue 185 | July/August 2020

PHOTO: BUNDESPOLIZEI KOBLENZ

(Right) Severe damage to slab track caused by a high-speed train fire.

A further, not-so-obvious benefit of slab track is that its use significantly reduces the area needed for the infrastructure maintenance depot at Calvert, which then doesn’t need to accommodate ballast and tamping machines.

Instead of these expensive assets, which have high maintenance costs, the machinery required for slab track maintenance is, typically, relatively simple gantries and concrete pumping machines.

Another benefit of slab track is that it eliminates the problem of flying ballast on highspeed railways, caused by a combination of air turbulence and ground bourne vibration, which can be a safety hazard and cause damage. In addition, there are workforce health and safety benefits from reduced exposure to dust, almost eliminating hand-arm-vibration, less working in proximity to machinery and a reduced chance of slips, trips and falls.

For the above reasons, HS2 concluded that, although ballasted track would be less expensive to install, slab tracks will have a lower whole-life cost, a lower whole-life carbon footprint and will avoid the need for the unacceptable disruptive maintenance and renewals associated with ballasted track. HS2 must take a longterm view and so, rightly, chose slab track.

Pre-cast or in-situ

Having decided not to use ballasted track, the next decision was what type of slab track should be used.

HS2 decided that it would use a pre-cast system, as this offers quicker installation with programme flexibility.

Furthermore, unlike in-situ cast track, it enables track defects to be repaired within HS2’s five-hour overnight maintenance window (eight hours at weekends). The need for such quick repairs was demonstrated in October 2018, when a train caught fire on the Cologne to Frankfurt highspeed line, near Dierdorf, closing the line for eight days. The intense heat of the fire caused significant damage to the slab track which had to be repaired before the line could be reopened.

For these reasons, HS2 ruled out widespread use of cast-in-situ slab track, such as the Rheda system, in which sleepers and steel reinforcement

INFRASTRUCTURE are cast into a concrete slab, as this requires rails to position the sleepers.

The alternative system of pre-cast panels only requires equipment that is easily transportable.

This offers the opportunity to lay the track slab simultaneously at multiple worksites. Another aspect that makes this possible is that this method of installation does not require the final rails to be in place, so they can be delivered later along the formation from a railhead.

Although great care must be taken with the surveying, the lifting gantries and grouting equipment needed to install pre-cast panels is relatively simple. Also, with hundreds of structures between Birmingham and London, it is almost inevitable that there will be some programme misalignment. Hence, it is important that track laying can leap-frog over any gaps in the formation.

Pre-cast panels are designed to be easily replaced within the available five-hour maintenance window. This requires removal of the rails, breaking the panel away from its base grouting layer, replacing the panel, grout it in position and leave it to set for three hours, re-rail and open the line at line speed the next morning.

This system also allows for minor settlement as, within limits, the fastening systems can be adjusted. For more significant movements, panels can be removed, jacked up and re-grouted.

Track contracts Before they can bid for the track installation contracts, prospective contractors need to know which pre-cast slab system is to be used.

Hence, the £200 million contract for the design, manufacture and supply of pre-cast slab track 08F-HS2SlabTrack-02 panels must be let several months in advance of 61 words the procurement of the track installation contracts, which will be let in 2022.

Slab track for HS2 For this reason, the track systems contract needs to be let early in the programme. Hence, in May, HS2 announced that it had invited tenders for a TABLE track systems supplier that will design and install around 280 route-kilometres of pre-cast track slabs, or around 80,000 panels, to be laid in a 20-month track construction window. The required

pre-cast system must be able to carry traffic at designated loads and speeds; meet the specified reliability, availability and maintenance requirements; have comparatively low whole life costs; allow slab renewals within engineering access windows; accommodate earthworks settlement within specified limits and facilitate high-quality production-line methods of construction.

The track systems contractor will be responsible for ensuring that its design ensures product approval and meets TSI requirements. It must also produce construction documentation to ensure that the track installation contractor installs the system to the required standards. The intention is that the track systems supplier will become a sub-contractor of the track installation contractor during the manufacture and supply of the pre-cast slabs.

There will be four track installation contracts that will lay track as shown in the table. The track systems contractor is responsible for thePage 1 of 1 design and supply of pre-cast slab track. The installation contractor for the Lot 1 (urban area) contract is responsible for laying cast in-situ track in tunnels. This will require the mitigation required to minimise GBSV in accordance with HS2’s specifications. The ballasted track to be laid by the Lot 3 (open route) contractor is for connection to Network Rail’s existing infrastructure.

Track installation - single track km Lot

Estimated Value £m

Total

Pre-cast slab

Cast in situ

in-situ or pre-cast slab

63

38

1

434

122

21

2

526

159

159

3

566

188

176

4

431

124

119

Total

1957

593

475

Ballasted track

S&C units

75 22 12

5 63

43

42 23

12

162

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INFRASTRUCTURE The shortlist

On the open route, except for on bridges, the track will be laid on an impermeable protection layer of high-quality granular material to protect earthworks from frost and water ingress by directing water to the drainage system. This protection layer, and the primary drainage, will be installed by the main works civils contractor.

The track installation contractors will then use paving machines to lay a concrete layer on top of this protection layer. As described later, the pre-cast panels are installed on top of this layer.

Rail Engineer | Issue 185 | July/August 2020

HS2’s website shows that the ITT shortlist for the track systems contract comprises two partnerships, each of which is between a precast slab system pioneer and a UK construction material supplier. These are the joint venture between Tarmac and Max Bögl, formed in 2016, and a partnership between Aggregate Industries UK and Porr Bau. The pre-cast slab system offered by Max Bögl is known as the FFB Bögl system. This is a development of a 460-metre trial prefabricated design that was laid in Karlsfeld Germany in 1977.

Porr Bau’s system is also known as Slab Track Austria, as it was jointly developed with Austrian Railways. Its oldest section has been in use since 1989.

The original trial tracks laid by both companies are still in use and have been maintenance-free since their installation.

Superficially, both systems look quite similar.

The Porr slab is 160 mm thick and 5.2 metres long and has eight pairs of rail fastenings. The longer 6.45 metre FFB Bögl slab is 200mm thick has ten pairs of fastenings. Both systems are laid on a concrete base that is, typically, 300mm thick.

The visual differences between the two systems are that the Porr slab has two rectangular grout holes while the FFB Bögl slab has breaking points between each pair of rail fastenings, to prevent uncontrolled crack development.

The Porr slab has two 920mm x 640mm tapered grout holes through which the selfcompacting concrete is poured to fill the 40mm gap between the elastomeric layer on the bottom of the slab and the concrete base. Before the pour, the slab is accurately positioned using five jacking screws (one at each corner and one in the centre) and reinforcement is placed in the tapered grout hole. When hardened, this tapered joint helps anchor the slab vertically and horizontally.

The FFB Bögl slab also incorporate spindles for the final adjustment of the slab, which is first positioned by Bögl’s slab positioning system. The 50mm gap between the slab and base layer is filled with a specially developed cement-bound non-shrinking grout that has good flowing and compaction qualities. The slabs are joined by turnbuckles, whereas there is no connection between the Porr slabs, which have the tapered grout holes for anchoring.

Worldwide experience Over the past 30 years, much track has been laid used using both the FFB Bögl and Porr systems. Of the two, the FFB Bögl system has had more worldwide use due to a technology transfer agreement with China, which resulted

INFRASTRUCTURE in its use for high-speeds lines such as Beijing to Tianjin (116 km) and Beijing to Shanghai (1,318 km). However, whilst there are thousands of kilometres of FFB Bögl track in China, in Europe there are only around a couple of hundred kilometres, mainly parts of German high-speed lines such as a 35-kilometre section of the Nuremburg to Ingolstad line.

Although there are no Bögl slabs installed on the UK network, the Tarmac/Bögl JV set up a 52-metre-long section of its FFB track at Tarmac’s Alrewas Quarry in 2018, for students from the National College for High-Speed Rail.

As of 2018, Porr Bau’s slab track system has been used to lay 782 kilometres of track worldwide. Apart from 165 kilometres in Doha, this has all been in Europe, with Porr slabs used for 281 kilometres of track in Austria and 320 kilometres of track in Germany. In the UK, the company’s pre-cast slabs have been used to achieve electrification clearance in Winchburgh tunnel (issue 130, August 2015) and on two track sections and a tunnel for the Gospel Oak to Barking project (issue 143, September 2016).

The Porr system was also used in Glasgow Queen Street tunnel to replace a deteriorating slab track that was almost 50 years old (issue 142, August 2016).

Both pre-cast slab track systems have a good track record. Yet, when assessing the experience of the prospective suppliers, HS2 will also have to consider the capabilities of

the UK collaborators in these partnerships.

These will have to supply huge quantities of construction materials, using around 700,000 tonnes of concrete for the manufacture of the pre-cast slabs, which will consume about a tenth of the UK’s total annual cement production.

In evaluating these bids, HS2 has much to consider in what could be a close contest.

Whatever the result, it is clear that HS2’s trackform decision will be thoroughly evaluated and informed by the worldwide experience of installing and maintaining thousands of kilometres of high-speed track over the past decades.

At least, Britain’s late membership of the highspeed rail club has had some advantages!

(Below) Porr slab track installation in Winchburgh tunnel in 2015.

(Inset) FFB Bögl slab positioning machine.

PHOTO: MAX BÖGL

PHOTO: NETWORK RAIL

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INFRASTRUCTURE

Slab Track

PAVING THE P-WAY

S

lab tracks, or, more properly, ballastless track systems, are becoming more widely used as alternatives to conventional

ballasted track.

There are many reasons for this, but, to understand them properly, we need to consider the difference between the two forms of track design.

In doing so, we shall attempt to keep the explanation as non-technical as possible, so we apologise in advance to those permanent way engineers who find our article too simplistic and lacking in detail. As always, Rail Engineer strives to find a happy medium.

Beauty of ballast Conventional track, which uses ballast, can be seen all over the UK. While it is the ‘traditional’ way of supporting railway tracks, it isn’t as simple as it looks, and it is quite demanding in terms of maintenance. It certainly is a lot more than ‘the stones that help keep tracks safely in place’ or ‘the stones that form the track bed’, as Network Rail often describes ballast to try and help regional press understand why the local railway is shut.

Of course, ballast does consist of stones, but rather special ones. They have to be a certain size, around 2550mm is considered to be best – one

early track guide, published in 1868, suggests that “no bit of broken stone be used as ballast larger than a man could put in his mouth”.

They also need to have sharp, angular edges, so they will interlock to keep the track in place, and they have to be of hard material so they don’t grind themselves into dust due to the constant pounding from passing trains.

Dust, and stones that are too small, will compact and stop the whole track system from draining properly.

When building a track, the first layer to go down is the bottom ballast. Laid 300-500mm thick, this is smoothed off and compacted to support the track’s sleepers. It can be laid very accurately using laser-guided bulldozers.

Actually, bottom ballast is often the second layer to go down. The first is a sheet of geotextile – in effect a ground sheet – that goes under everything. This textile is carefully designed to allow water to pass through, so the track will drain, but not to allow particles of dirt and mud back the other way. This prevents the vertical movement of the track caused by a train to ‘pump’ dirty water up from the subsoil or embankment, so contaminating the ballast.

Once the bottom ballast is laid, compacted and levelled, the track is then placed upon it. Finally, more

Pouring ballast shoulders at Leeds station.

Installing the first pre-cast slab track at the entrance to Winchburgh tunnel alongside the existing ballasted track.

Rail Engineer | Issue 185 | July/August 2020

INFRASTRUCTURE

Tamping track on the approach to Crick Tunnel between Northampton and Rugby.

ballast – the top ballast – is spread over everything and arranged so that the voids between the sleepers are filled, to stop the track moving fore and aft, and so that a pronounced hump or bank – the shoulder – is in place over the sleeper ends, to prevent the track moving sideways.

Well, that’s all the theory. In practice, trains make the track bounce up and down, compacting the bottom ballast still further in places and resulting in voids and an uneven track geometry. The stones rub together and start to wear away, creating dust and fine particles, and the whole track moves a bit to the left or right, or perhaps both.

The cure is to ‘tamp’ the track.

Large machines lift the track clear of the bed, agitate the ballast under it, restoring volume where the ballast was compacted, and lay the track back down again. Again, these are laser controlled and very accurate – they are the same machines used to give the finishing touches to newly laid track so as to put it on an even level.

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INFRASTRUCTURE If the ballast has too many voids, a ‘stoneblower’ can be used instead, which does a similar job of temporarily raising the track but this time blows fresh new stone under it to fill those gaps.

Eventually, the whole ballast bed will need replacing – ballast can last around 20 years (depending on traffic) while the other track components can be double that. A ballast undercutter will raise the track, dig out the ballast, replace it with fresh and relay the track. Sometimes it even screens the old ballast, so good stones can be reused and only the bad ones are replaced.

A high-output ballast cleaner is immense. To replace one mile of ballast in one overnight shift needs a machine that is half a mile long (and includes 44 wagons to deliver new ballast and store extracted spoil) and costs £50 million. Plus, to get into those difficult areas such as in amongst points and crossings, another machine that looks like a giant vacuum cleaner is needed to suck the ballast out of the ground.

So, in short, ballasted track is more costly to lay than it looks, needs regular maintenance, which is also expensive, and has to be completely replaced every 20-40 years.

And we haven’t even discussed how wayward ballast stones get in the drains and clog them, how the draft from highspeed trains picks up the stones and throws them about, causing damage to both the train itself and the rails, and how sideways movement can reduce clearances between the track and lineside structures (or other tracks).

Checking the alignment of freshly laid track (Bruggwald tunnel, Switzerland).

Alternative slabs It’s now easier to understand why a solid track form, that can almost be forgotten once it is laid, could be so appealing.

There are two main types. One is cast in situ. A base layer, usually concrete, is laid over a prepared and compacted substrate. Sleepers are placed over this, though often they are just a pair of concrete blocks joined by steel rods to keep them the correct distance apart.

Then the rails are laid on those blocks and clipped into place.

Finally, wet concrete is poured between the sleeper blocks. Once this is set, the track is essentially one homogeneous mass.

It won’t move anywhere, anytime soon.

Pouring concrete to complete a cast-in-situ system in a twin-track tunnel (Bözberg tunnel, Switzerland).

Rail Engineer | Issue 185 | July/August 2020

This type of system is currently being used on the West Midlands Metro extension in Birmingham.

A more advanced system is to form the track slab from individual precast panels. These are manufactured offsite and are then installed and aligned on a prepared sub-surface, again usually concrete. They can be positioned very accurately and adjusted using jacking screws in the corners of the slabs.

Once in place, they are secured by having grout (another form of concrete) pumped underneath them both to spread the load away from the jacking screws and to fix them in place.

The advantages over a cast-in-situ system are that the slabs can be manufactured and positioned with great accuracy, they can be laid piecemeal so gaps can be left where infrastructure works still need to be completed, the rails don’t need to even be present when the slabs are installed, and they can be replaced individually if damaged.

The downside is they are more expensive to install than both castin-situ and ballasted track, but a lot cheaper to maintain.

When installed in tunnels, both types of slab track can be laid with a resilient layer between the slab and the concrete tunnel lining. This prevents the transfer of noise and vibrations from the track slab into the tunnel structure and so to the ground above. For this reason, the track in the Crossrail tunnels consists largely of one of four types of resilient track, depending on the location.

INFRASTRUCTURE In-house innovation All of these systems need experienced installers and maintainers to get the best out of them. New railway construction could use two, or even all three, types of track along its length, so the installer has to be versatile.

Rhomberg Sersa has been building slab-track railways since the 1970s and has developed a well-grounded technical expertise across all the various slab track systems and alternatives. The company has even used this experience to develop its own IVES ballastless track system, which is both cost effective and easy to install in confined spaces.

IVES, which stands for intelligent, versatile, efficient and solid, uses a narrow pre-manufactured slab, looking more like a traditional railway sleeper than the larger slabs used in most other systems.

The sub-surface layer is usually asphalt, laid as a conventional roadway and finished using road-roller technology. The rectangular slabs are placed across the line of the finished track, evenly spaced.

The whole track is then assembled and rails fastened into the clips on each ‘sleeper’, largely by hand in areas where heavy machinery would find access difficult. At this stage, the tracks themselves can now be used to access the rest of the worksite.

When everything is finished, the final adjustments are made and everything is grouted into place. A few hours later, and the line can open for traffic.

The IVES system installed in a tunnel.

Rhomberg Sersa also turned its attention to where conventional ballasted track transitions into slab track – perhaps at a tunnel portal or at the start of a bridge deck. Here, the difference in track fixity means that the settlement of ballast stones at the interface results in voids or hanging sleepers in the track adjoining the slab track or bridge, giving rise to higher forces and damage as trains traverse the ‘dip’.

The solution is V-TRAS, a steel cantilever on which the first few sleepers of the ballasted track sit, giving them additional support thereby providing the rail with additional support and spreading the impact of any potential dip to counter the differential settlement.

New Bailey Street bridge Both innovations were used back in 2017, when the Rhomberg Sersa Rail Group was contracted to develop a

low height, low weight slab solution for New Bailey Street bridge deck/track replacement as part of the Northern Hub project.

For the bridge itself, a plinth variant of the IVES slab-track system was selected but, due to the design requirements of the new bridge, a completely new method of fixing was developed that allowed for plinth removal/replacement in the future.

Each plinth unit had four, specially designed spindles and anchors to secure it that sat within core-drilled apertures in the bridge deck – precisely located to match the plinth geometry. Once positioned, the plinths were then lifted to height using the spindles, shuttered, and a high-specification grout poured through the plinths to fill the voids under them, surrounding the spindles and anchors.

New Bailey Street bridge.

Rail Engineer | Issue 185 | July/August 2020

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INFRASTRUCTURE This design allows for the fast and effective removal/replacement of any single plinth, if that should ever be required.

Once the rail was in its final design position, and an accuracy of ±1mm was achieved, grout was poured to stabilise and fix the baseplates.

A V-TRAS cantilever system was fitted to create the ballast-to-slab transition.

Winchburgh tunnel In 2015, as part of EGIP electrification, Winchburgh tunnel, just east of Linlithgow on the route out of Edinburgh Waverley station, required track lowering up to 200 mm and the installation of slab track at a cost of £17 million. This was an essential element of the Edinburgh to Glasgow electrification programme, which was set to transform train services across Scotland’s central belt.

The tunnel is 388 metres long and has a pointed roof profile. Lowering the track by up to 200mm, together with the use of a Furrer+Frey rigid overhead conductor rail system (ROCS), would just be sufficient to provide the required electrification clearance. To ensure this clearance was maintained, the track had to be fixed in position, requiring the installation of slab track. This would significantly reduce track maintenance and increase speed through the tunnel from 80 to 90 mph.

Principal contractor Morgan Sindall chose the ÖBB-PORR ‘Slab Track Austria’ system – the first time that it had been used on the UK rail network, although it had already been trialled on the Old Dalby test track in Asfordby tunnel.

Winchburgh tunnel.

The system was jointly developed by Austrian Railways (ÖBB) and concrete construction specialist Porr, based in Vienna. It was first used in 1989, has been Austria’s standard slab track system since 1995, and has also been widely used in Germany since 2001, where the Erfurt to Leipzig high-speed line used 180km of it.

The principal element of the system is a 160mm thick concrete slab that has up to eight pairs of track fastenings. There are different geometries for straight track and different curves. The slabs are fixed to a foundation layer using self-compacting concrete (SCC) that is poured through rectangular tapered openings in the base plate after it has been accurately positioned using the five jacking screws in the slab.

The pre-cast slab incorporates an elastic rubber coating which absorbs vibration. This coating also serves as a barrier between the slab and the SCC, enabling it to be easily broken out in the unlikely event that it should need to be replaced.

Rhomberg Sersa had installed the Slab Track Austria system in Asfordby tunnel for the trial and was now contracted to install the 188 five-metre slabs in Winchburgh tunnel during a 44-day blockade.

The concrete base slab was poured by Babcock, after which it took Rhomberg Sersa two days to accurately position all the slabs on one line. When there were sufficient slabs in place, 110-metrelong rails were fitted on them to ensure accurate positioning.

Watertight formwork was needed as the SCC is very fluid. After the SCC pour, it took 24 hours before the track could carry traffic. The slab track was then complete, and the process was ready to be repeated for the down line.

Queen Street tunnel

Grouting Porr units in Queen Street tunnel.

Rail Engineer | Issue 185 | July/August 2020

One year later, and attention switched to the Queen Street tunnel. Much longer than Winchburgh, at 1159 yards, the twin-track tunnel already had slab track, fitted in the 1970s in a bid to reduce maintenance costs. However, it had deteriorated badly after 40 years of use, so, with the need to both replace 1.8 kilometres of tunnel slab track and undertake station throat works, a lengthy closure of Scotland’s third-busiest station was inevitable.

Rhomberg Sersa Rail Group // One of Europe’s leading railway contractors and the UK’s leading specialist of slab track design and construction We are a full railway engineering service provider, offering a comprehensive range of services in the fields of railway construction, enhancement and maintenance, with unparalleled experience across the full spectrum of slab track engineering.

Our portfolio covers the design and construction of slab track solutions, track renewal and maintenance, tunnels, stations, consultancy, planning and design.

We operate as consultant, designer and contractor throughout the project lifecycle, including design and build projects as a main contractor and sub-contractor.

Our Capabilities and Products include: • Design & Consultancy • Infrastructure Engineering • Slab Track

• Specialist Products & Services • Machine Group – state of the art material handling • Survey Services

Rhomberg Sersa UK Ltd | 2 Sarah Court, Yorkshire Way, Doncaster DN3 3FD T +44 (0)300 30 30 230 | www.uk.rhomberg-sersa.com | enquiries@rsrg.com

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INFRASTRUCTURE On 20 March 2016, Queen Street High Level station was closed for twenty weeks.

During this time, a comprehensive plan ensured that passengers could get to Glasgow, albeit with extended journey times. Trains were diverted to the Low Level station or the city’s Central station, additional use was made of the line via Airdrie and Bathgate and extra local buses were provided for travel to local stations.

Rhomberg Sersa was contracted to install a Slab Track Austria (STA) plain-line slab system, as well as a Sonneville LVT slab system for the switches and crossings (S&C) within the tunnel.

Unlike Winchburgh, the Queen Street work required the removal of the previous slab track. A trial breakout had been undertaken during the previous December, to confirm the proposed methodology. This removed 20 metres of the tunnel slab track, which was then temporarily replaced with ballasted track.

Once the blockade started, tunnel, lighting, ventilation and communication systems were installed and a coring machine was used to prepare the slab track for its removal. Story Contracting was responsible for the removal of the old slab track, constructing a concrete base layer for the new slab track and installing a new drainage system between the Up and Down base slabs. Due to the restricted access, the concrete for the base slabs had to be supplied through the two original tunnel construction shafts.

The base slabs were completed by 19 May, and Rhomberg Sersa began installing the 5.2-metre-long, 160mm thick STA slabs on the Up line. This was completed by 3 June, work moved on to the Down line and the whole station reopened on 7 August as planned.

Loading Porr STA slabs to go to Glasgow Queen Street tunnel.

Further work Since those two major projects in Scotland, Rhomberg Sersa has installed a number of sections of slab track around the network. On the Gospel Oak to Barking line, three sections of slab track were installed under bridges and more in the tunnel at Crouch Hill, totalling approximately 1,400 track metres. Twelve V-TRAS transition units, one at each interface between the slab and ballast, were also fitted.

Most recently, Rhomberg Sersa is fitting slab track inside Gasworks tunnel at London King’s Cross, bringing a third bore of that tunnel back into use to expand capacity at the London terminus.

Slab track isn’t the only option for modern railways and ballasted track will be around for many years to come – probably for ever. Rhomberg Sersa certainly hopes so, it also has a good business replacing conventional track

Installing a V-TRAS system at New Bailey Street.

Rail Engineer | Issue 185 | July/August 2020

through stations and in hard-to-reach places using its innovative Machine Group ballast removal and delivery train.

However, slab track is definitely the way to go in some applications. For high-speed railways, in tunnels with tight clearances, on bridges where weight and access for maintenance are issues – all of these are ideal applications for slab track.

As we have shown, there are several forms of slab track as well – they, too, have their particular applications.

The common thread is Rhomberg Sersa.

Whichever form of slab track is chosen, the installer needs the experience to do the job properly, safely and on time. And if that installer can also ‘tweak’ the design where needed, or come up with its own solutions, then so much the better.

Thanks to various Rail Engineer colleagues whose words of wisdom have been shamelessly ‘borrowed’ for parts of this article.

FAST TRACK TO SUCCESS

SLAB TRACK SOLUTION WITH ACCURACY AND DURABILITY

Stabirail has designed and developed a new technology for slab track construction in tunnels and railway stations.

• Fast working method • 2mm accuracy • Reduced vibration to the tunnel construction and buildings above • Shallow construction height of the tunnel • Reduced dead load • Higher speed operation • Very low maintenance requirements • Long design life • Low whole-life cost • Rail System and Design Independent

For more information, contact Gerrit Roelants +32 475 214 607 gerrit@stabirail.com

www.stabirail.com

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INFRASTRUCTURE

Rail Engineer | Issue 185 | July/August 2020

INFRASTRUCTURE

The station now arriving OLD OAK COMMON INTERCHANGE

T

hree and a half miles to the west of Paddington Station, in north-west London, is the location of the former Old Oak Common Great Western Railway and Heathrow Express depots and a number of industrial sites.

In 2015, this area was identified for a major regeneration project by the Greater London Authority. The site lies within three separate boroughs - Hammersmith and Fulham, Ealing and Brent.

The Old Oak and Park Royal Development Corporation (OPDC) was established to develop a new centre and community for West London.

The site includes the intersection of the underconstruction HS2 tunnels, the Elizabeth line (Crossrail) and National Rail’s Great Western lines.

The OPDC was charged with transforming one of London’s most inaccessible areas into a well-connected, world-class transport interchange, as well

as providing new housing and commercial development, surrounded by sustainable and thriving neighbourhoods and valued amenity space. It has committed to create tens of thousands of new jobs and homes over the next 20 years.

The project is vast and will be the largest regeneration project in London since the preparations for the 2012 Olympic Games in east London.

The new Old Oak Common station Permission for the construction of the new high-speed railway between London and the West Midlands was granted

by Parliament through the High Speed Rail (London-West Midlands) Act 2017 (‘the HS2 Act’).

Under the Act, OPDC is the planning authority for the redevelopment of the whole 640-hectare (1,580 acre) site. In April 2020, under Schedule 17 of the High Speed Rail Act, it granted planning consent for the construction of the new Old Oak Common interchange station.

BOB WRIGHT

Rail Engineer | Issue 185 | July/August 2020

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The station will link Elizabeth line (Crossrail), HS2, Heathrow Express and GWR services to the West and Midlands.

It will have 14 platforms and will be used by up to 250,000 passengers each day.

Six sub-surface platforms will serve the high-speed HS2 services to the Midlands, North and Scotland, with services to Euston in nine minutes and to Birmingham Curzon Street in 38. These platforms will be capable of being operated as a London terminus, ahead of the completion of works at Euston.

This will be the largest subsurface station built in the UK, with a box structure 850-metres long and 20-metres deep.

Eight surface platforms will serve the Elizabeth line (Crossrail), taking passengers to Heathrow and Central London, and the Great Western main line, for GWR’s trains to Wales and the West of England.

High-quality passenger and retail facilities will be incorporated into the new station.

In conjunction with the OPDC masterplan, Transport for London proposes to construct

Rail Engineer | Issue 185 | July/August 2020

two new London Overground stations, at Hythe Road and Old Oak Common Lane. These will be close to the new Old Oak Common station and will increase the interchange opportunities for travellers.

Outside the station building, above the HS2 box, there are options to create a public park, to include broad-leafed trees, water features and outdoor event spaces. Alongside this will be a surface transport hub, providing local connectivity to buses, cycle routes, taxis as well as ‘kiss and ride’ drop-off and pick-up areas.

HS2’s stations director Matthew Botelle said that “HS2 is set to be a catalyst to transform this area of West London, making it one of the best-connected development sites in the UK”.

Architectural The new station will be the largest ever built in the UK as a single project. Only once in several generations does a project of this scale occur.

The station design development has been led by WSP and architects WilkinsonEyre, working with

INFRASTRUCTURE HS2 to develop conceptual designs. These were presented to the general public and local community early in 2019 through a series of engagement workshops that included 3D physical models as well as Virtual Reality walkthroughs.

The purpose of these engagement workshops was twofold - to keep the community informed about potential impacts during construction and to encourage residents, public organisations, businesses, charities and voluntary sector organisations to understand the station design objectives and to influence how the public space might be used.

The independent design panel for the project was a 50:50 arrangement between HS2’s design panel and OPDC’s place panel. Regular presentations and workshops took place during the design phase. Network Rail’s built environment development and accessibility panels also received presentations on the project.

The various rail alignments were fixed so the station site was constrained within a triangular shape and the designers’ challenge was to find an architectural form that worked for a single station serving three, very different rail networks.

The station will have six highspeed platforms underground with an integrated connection to the adjoining conventional platforms at ground level along a central thoroughfare. A light and airy concourse will link the

two parts of the station, unified by a vast soaring roof inspired by the rail heritage of the site, its large span roof reflecting Victorian train sheds.

This new station will be very unusual as only 20 per cent of passengers are expected to enter the station by road or on foot. 30 per cent are expected to transfer between HS2 and the surface lines and the remaining 50 per cent transferring between the Elizabeth line and National Rail.

The design responds to these

HS2 CEO Mark Thurston explores OId Oak Common through augmented reality and (overleaf) on the ground.

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INFRASTRUCTURE passenger movements and will ensure seamless interchanges between train services and the bus, walking and cycling networks.

In addition to the works on the station site itself, Old Oak Common Lane will be lowered and widened to improve access to the station for buses and pedestrians. It will also be realigned to allow for the footprint of the potential new London Overground station.

Three elements The station will be made up of three elements, the surfacestation area, the HS2 station box and shared buildings for plant, retail and back office services.

An important design strategy was to get as much natural light into the station as possible.

The architects and engineers worked together to maximise the light entering the station, with visually attractive and standardised connections.

The rooflights cover the whole station and are integrated with the ventilation requirements for natural and smoke venting. The HS2 box includes large light wells above the platforms.

Rail Engineer | Issue 185 | July/August 2020

The station’s ‘stork wing’inspired roof will likely be the iconic feature of the project and provides an opportunity to harness solar energy through photovoltaic panels, rainwater harvesting and natural ventilation.

The roof’s geometry was complex, given the tapering shape of the site, and is based around triangular shells. Excellent and efficient passenger movement around the large site was a vital part of the design approach. Its large single span of up to 60 metres reduces visual obstructions and provides a vista across the

station. This will ease navigation for passengers and provide an intuitive environment, minimising walking time from platform to platform. A central cathedral-like 25,000-squaremetre concourse area leads into clear routes to all parts of the station and includes 34 staircases, 44 escalators and 52 lifts.

The structure of the roof will be fully exposed. The main beams will be large box sections with tied secondary arches, all in weathering steel. The boxes are of varying thickness but constant geometry for visual continuity.

INFRASTRUCTURE The smooth shape and connection detailing will limit pigeon roosting problems.

The footbridges across the surface platforms will be simple structures of precast elements on spine beams, for easy maintenance and to reduce future inspection and possession requirements.

The design was challenged to optimise carbon and cost.

Value engineering using wind tunnel tests resulted in a 27 per cent reduction of steel in the roof, saving over 1,000 tonnes and ÂŁ7 million on the original concept design.

The main station accommodation building beneath the roof will be three storeys high and will be independent of the structure, so that the roof or buildings can be independently altered to reflect any future requirements.

Sustainability The station has BREEAM (Building Research Establishment Environmental Assessment Method) rating

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of Excellent+. Its design and materials will reduce energy usage, materials, waste, and minimises environmental impact. The design also meets HS2’s zero-carbon targets.

The roof features passive design to minimise the need for climate control beneath it; with north-face glazing to reduce glare and solar gain and the south-facing side carrying photovoltaic cells. Runoff will be contained in large buried attenuation tanks before being discharged from the site into the existing Stamford Brook sewer.

Ventilation will be provided by passive fixed louvres in the glazing, with further active vents for release of smoke in the event of an emergency. The only mechanical ventilation will be at the west end of the HS2 box, to vent the area beneath the park.

Station box and tunnels The HS2 station box is the most substantial element of the project. Its dimensions reinforce that. It will be 850 metres in length, 70 metres wide and 20 metres deep and will involve the excavation of 740,000

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INFRASTRUCTURE for the HS2 tunnels and also provide emergency escape routes from the tunnels.

Construction of the station box is due to start in the autumn of 2020 as it will also form the reception pit for the short bore from Victoria Road, to the west, and the launch pits for the tunnel bores to Euston at the east end of the box.

Timeline

Old Oak Common augmented reality table.

cubic metres of London Clay.

Drainage will be provided to prevent flotation over its 120-year design life, although permeability is very low.

Some of the arisings may be reused elsewhere on the wider regeneration site or removed offsite using a long conveyor.

The box diaphragm walls will be 1.8km in length. The internal support to the HS2 station superstructure will be provided by 25-metre deep-bored piles, 1.8 and 2.1 metres in diameter, with large fabricated plunge columns within. Value

Rail Engineer | Issue 185 | July/August 2020

engineering of this structure resulted in the substantial saving of 230 of these large diameter piles.

The walls will be propped by 3.5-metre-square beams at 13 metre centres. These are shaped to receive light in a way that will soften the visual impact and maximise the amount of natural light reaching the platforms. The western end of the box will be roofed by a slab carrying the public realm area.

Head houses at each end of the box will provide ventilation

HS2’s enabling works contractor, Costain Skanska JV, has made considerable progress on the site, with the former rail depot sheds and outbuildings demolished and 105,000 cubic metres of excavation completed.

Permanent works on the site are to be delivered by a Balfour Beatty, Vinci and Systra (BBVS) joint venture. These began in June 2020 and will be completed ahead of the start of the HS2 railway service in 2028-31.

Rail Engineer will certainly return to this landmark project over the next few years.

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The chosen product for rail and depot rooflights is the innovative Multi-Link-Panel NF (Non Fragile), its fix and link method of installation is incredibly quick to fit, making it an excellent choice for installation in stations where possession times are an issue.

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INFRASTRUCTURE

A

Docklands Update

CLIVE KESSELL

F

or many of the older generation, including your writer, it only seems like yesterday that the Docklands Light Railway (DLR) first opened, but in fact it was as long ago as 1987. In the intervening period, a lot has happened and in a recent talk given to the IRSE London & SE section, DLR was described as a ‘Trainset to Metro’. A number of challenges are emerging with the signalling and control systems, which were state of the art at the time but are now coming up for renewal.

As always with a busy metro railway, thousands of people are carried every day, so any disruption to travel is a major concern.

To understand the scale of the problem, one first needs to know the history of DLR and how it has expanded.

DLR history In 1984, the old London docks were empty, with big plans afoot for a total regeneration of the area. To complement the building developments, a transport system would be needed, so the DLR was originally planned as a Y-shaped network with Tower Gateway in the west, Stratford in the north and southwards to Island Gardens on the north bank of the Thames.

By 1996, the Canary Wharf development was well advanced, massive new development schemes being projected beyond the original Docklands area. The DLR has had to keep pace with these.

In chronological order, the railway has grown as follows: » In 1987, the Y-shaped route opened at a cost of £77 million with 13 route kilometres and 15 stations. Trains were a single articulated vehicle with a maximum speed of 80kph and able to negotiate a 40-metre radius curve.

Signalling was a GEC fixed-block SSIbased system (solid-state interlocking) with automatic train operation (ATO) and a 10-minute frequency.

» In 1991, an extension to Bank station opened, costing £149 million with a 1.6km twin-bore tunnel branching off prior to Tower Gateway via a steep descending gradient. This gave much improved access to the City, although Tower Gateway was retained. » In 1994, the extension from Poplar to Beckton was opened, costing £224 million and embracing 10 new stations with the route constructed mainly on viaducts. The original trains were replaced with ones capable of two-vehicle operation. This extension anticipated regeneration of the area, which is still ongoing. » Also in 1994, the original signalling system was replaced with the Alcatel (now Thales) Seltrac moving-block system similar to that used on the

Tunnel boring machine breaks through at Woolwich Arsenal, July 2007.

Rail Engineer | Issue 185 | July/August 2020

Stratford International

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INFRASTRUCTURE

Stratford

Stratford High Street

Skytrain metro in Vancouver, using track loops for track-to-train transmission and a much-improved service frequency. Seltrac is a proprietary Communications Based Train Control (CBTC) system. Significant increases in ridership were the catalyst for all of this and the service pattern was changed to three basic routes - Bank to Island Gardens, Bank to Stratford and Tower Gateway to Beckton. » In 1999, DLR was extended south of the Thames to Lewisham, from a relocated underground Island Gardens station through twin-bore tunnels and five new stations. The cost was £200 million, with finance raised via a PFI (private finance initiative) concession, which will cease in 2021 after which the line will be absorbed into the main DLR business structure. » In 2005, a branch from Canning Town to King George V opened. It cost £140 million and had four intermediate stations, principally London City Airport.

This, too, was financed differently but not in such a restrictive way as for Lewisham.

A fourth operational route from Bank to King George V commenced. » In 2009, the branch was extended from King George V to Woolwich Arsenal by another under-river crossing of 2.5km

Pudding Mill Lane

Devons Road

Bank

Langdon Park

Tower Gateway

Limehouse Shadwell

Westferry Poplar West India Quay Heron Quays

Abbey Road West Ham

Bow Church

All Saints

Star Lane Canning Town Royal Victoria

East India Canary Blackwall Wharf

Royal Albert

Custom House West Silvertown

South Quay

Beckton Prince Regent

Cyprus

Beckton Park

Pontoon Dock

London City Airport

Gallions Reach

King George V

Crossharbour Mudchute

Island Gardens

Woolwich Arsenal

Cutty Sark Greenwich Deptford Bridge Elverson Road Lewisham

twin-bore tunnels and a 13.5 metre diameter intervention shaft . » Finally, in 2011 and in anticipation of the London Olympics, a new link to Stratford International from Canning Town was created, using part of the former North London line to North Woolwich. This cost £150 million and included four new stations.

As a result of all of these additions, the current network is 40km in length with 45 stations.

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Other major enhancements In addition to the line extensions, other major works had to be undertaken to cope with the growth in passenger numbers and new housing developments.

A brand-new station at Langdon Park between Poplar and Stratford was constructed in a futuristic architectural style, with much use of curved glass.

The increase in ridership meant that two vehicle trains were often insufficient and a project was put in place to increase train

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Rail Engineer | Issue 185 | July/August 2020

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INFRASTRUCTURE length to three vehicles. This proved very complex as it meant lengthening platforms, many of which were already in cramped locations.

The two-track island platform arrangement at Tower Gateway was abandoned owing to space limitations, so the station has been rebuilt for just one track, with platforms either side (see right). This enables the segregation of incoming and outgoing passenger flows.

At South Quay, it was impractical to lengthen the existing two platforms, so the station was rebuilt on a totally different site nearby. With a busy operational railway, closing the railway to undertake the construction was impractical, so working every night was the only option.

Platform extensions were also impossible at five other stations - Cutty Sark, Elverson Road, Pudding Mill Lane, Gallions Reach and Royal Albert - so selective door opening had to be introduced with the first and last set of doors on the three-vehicle train that are inhibited.

As well as platform lengthening, enhancements to both traction and lowvoltage power supplies were needed, plus some additional lifts and expansion of the long-line public-address and CCTV networks. Additional trains were purchased from Bombardier in Germany, bringing the fleet total to 149 vehicles.

Flat junctions are always a source of delay when operating an intensive service and two such junctions existed on the DLR. The first, at Delta junction on the original part of the railway, where the lines from Bank, Poplar and Canary Wharf interconnect in a triangular formation, was the most critical. To obtain grade separation, the eastbound track from

West Ferry to West India Quay had its viaduct repositioned, using both some of the original spans and some new ones as well, to dive under the West India Quay to Poplar track, thus avoiding conflicting movements. A small penalty was that west-to-south trains could no longer call at West India Quay - the track being at a different level - but, with Canary Wharf station only a short distance away, this was a small price to pay. The work was completed in August 2009.

At Canning Town, a similar situation had existed with the opening of the London City Airport line. A new flyover was installed to grade separate this junction.

Ageing railway As has been described, DLR has grown piecemeal over the years and the original Seltrac equipment is now a 25-year-old design. As the later extensions have opened, different marques of equipment have been introduced, sometimes needing to alter the boundaries of the CBTC sections.

Delta junction opened in August 2009.

Rail Engineer | Issue 185 | July/August 2020

Seltrac works with four essential components: » VCC (Vehicle Control Centre) and SMC (Schedule Management Centre) located at Beckton and Poplar control centres, which give out the train commands to the various subsystems; » VOBCs (Vehicle On Board Controllers) that are fitted on every train; » SCSs (Station Controller Systems) providing point and emergency stop button supervision; » ACEs (Axle Counter Evaluators) and associated axle counters that provide deadlocking and a means to track non-communicating trains at specific places on the journey by providing a secondary train detection facility.

The communication between track and train is carried out by continuous inductive track loops (sometimes known as wiggly wire) that are laid between the running rails. If communication is lost between the control centre and the train, then the train stops before proceeding in restricted mode to the next loop section, with other trains in the vicinity being vitally protected.

The system is very reliable. The VCC at Beckton is relatively new, with sufficient capacity to handle any future extensions or remodelling projects. The SCSs are of different vintages and the interfaces between these and the ACEs have needed a new design to accommodate the incremental upgrade of the ACE equipment. Thales has worked hard to ensure the variations in the design of the equipment all work together successfully.

However, warnings have been given that ongoing support for the present arrangement will need re-thinking in about three years due to difficulties in the sourcing of old components.

INFRASTRUCTURE Options for upgrading DLR management has worked out four likely options: » Do nothing and trust that the existing system configuration will remain reliable and that in-house resources can faultfind and repair any failures that occur.

This is rejected as unsustainable in the long term. » Buy up the remaining stock of spares from Thales to ensure piece parts are available for a longer period of time. This eventually has the same unsustainability, but over a longer period of time, and is not supported by Thales as it weakens its ability to give third-level assistance when needed, both for DLR and other similar systems that still use this technology. » Place an order for new equipment and spares to be manufactured whilst it is still possible to do so, such that a longer period of guaranteed service provision can be maintained. Again, Thales advises against this as it is perpetuating an obsolete system which will only delay an inevitable upgrade to a more modern design. » Upgrade the system to the latest hardware, broadly to the design being rolled out by Thales on the London Underground sub-surface lines (the 4LM programme - four lines modernisation).

Whilst the third option is the most cost effective, it doesn’t have full support from Thales so it is doubtful as to whether this will overcome the obsolescence challenges. Backward compatibility with the remaining equipment might also be problematic.

Option four is effectively a re-signal of the wayside network and is obviously the most expensive, but there are other

The signalling and control system is now 25 years old and in need of replacement. factors as well. The new equipment has two generation options - Third Generation, where racks have a bigger footprint than the existing and space constraints will be a problem in some equipment rooms, or Fourth Generation, which is currently not used anywhere but has a very distributed approach to the architecture of the design.

On the plus side, the present SCSs, which number 30, could be reduced to 17 but may require more fibre cable capacity, dependent upon cut-over strategy and the need to cater for the additional data.

Also, if one SCS were to fail, it would mean losing a larger section of the railway.

Deliberations continue as to the way forward.

Future Expansion and Other Issues New routes are always a possibility.

One, to Dagenham Dock from a junction off the Beckton branch, has been under consideration for some time but is not likely to proceed in the short term. More likely are additional under-river crossings to either Catford and/or Thamesmead, both seen as growth areas.

Other system technologies will have to be modernised in time. The inductive track loops are no longer the preferred transmission system for new automated metros, radio now being the system of choice. However, on DLR, there is no plan to change to radio as the loops give reliable service. Any new signalling equipment will be bought with a future radio capability.

Similarly, the DLR radio network for communication to trains and staff has been upgraded in recent years, to improve coverage and reliability, but it remains an analogue system.

Sooner or later, a change to digital technology will be required, but not yet.

DLR has a ‘can do’ ethos and there is no doubt it will arrive at workable solutions for all the challenges ahead.

Thanks to Geoff Mitchell, who is head of engineering for London Rail, encompassing DLR, London Trams and London Overground, and who gave the presentation to the IRSE.

Rail Engineer | Issue 185 | July/August 2020

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FEATURE

EYES ON THE NETWORK

P

assengers and staff increasingly rely on information about journeys, networks and other facilities to ease circulation around the transport system. A reliable supplier which also offers design support can elevate display technology for all users and meet the needs of a connected transport system.

There are many display and touch screen choices available, each with its own features and characteristics.

Relec Electronics offers a range of Thin Film Transistor LCD (TFT) displays, with or without integrated touch screens, from 1.77 to 31.5 inches in size. Rather than a standard display, the specialist engineering company is able to tailor a solution for the required environment, whether inside a driver’s cab, on shielded platforms for passenger information, or in exterior locations where they are subject to extremes of temperatures but also subject to heavy use (for example ticket machines).

Technology choices TFT displays can be constructed from a number of different technologies, but today’s market is dominated by two, TN (Twisted Nematic) and IPS (In-Plane Switching).

TN technology has been around for many years, with displays available in a wide variety of standard sizes. TN displays are generally cost effective, have fast pixel response times and consume little power, but they suffer from poor colour reproduction, low contrast ratios and limited viewing angles.

IPS technology has solved many of these problems, providing virtually 180° viewing angles. IPS technology arranges and switches the alignment of the crystal molecules between the glass substrates, which reduces the amount of light scattered in the matrix and also results in higher contrast ratios and improved colour reproduction.

Reduced glare and improved strength TFTs are susceptible to glare and reflection from either bright light or direct sunlight, making it difficult for a viewer to see the information clearly. Clear visibility is particularly important in instrumentation in the driver’s cab but is also desirable in passenger information systems. Glare and reflection can be dramatically reduced by the addition of an optical bonding layer.

Optical bonding introduces an optical compound, usually a gel, between the cover glass and the TFT. This layer helps to minimise trapped moisture and reduces the effects of fog in the display, to ensure a clear view. By reducing the internal reflection, the display’s contrast is increased and the screen is more visible in bright conditions, without the need to increase the brightness levels, which would increase power consumption.

The process also enhances the strength and durability of displays, which may be located in high-thoroughfare areas, such as ticket halls. It prevents condensation and the ingress of contaminants, which can threaten the display’s operation. The process improves resistance to vibration and moisture, adding to its reliability and also optimises its performance in harsh temperature environments.

Displays can be further strengthened by the addition of a toughened cover glass, up to nine millimetres thick, to further increase durability and vandal resistance.

This feature is particularly useful in ticket machines and public areas, and where downtime due to damage and repair needs to be kept to a minimum.

Rail Engineer | Issue 185 | July/August 2020

Polarisers Another option available to display integrators is fitting anti-reflective (AR) or quarter-wave polarisers. An AR polariser is a clear film that is applied to the panel to reduce the amount of reflection created by bright external light.

In a typical TFT display, there are three layers through which light passes, namely the cover lens, an air gap, (which can be optionally filled using an optical compound) and the TFT panel. Within each of these, there is a reflection of approximately five per cent under direct light, making a total of 15 per cent reflection.

The AR polariser reduces this to approximately nine per cent. Up to three layers can be applied to a single display to further reduce the reflection. For example, using two layers reduces the reflection to five per cent and, with three layers, the reflection is reduced even further, to just 0.5 per cent.

AR polarisers can be applied to the top or bottom of the cover glass, or to both to further reduce reflection. However, if the display has a projective capacitive touch panel (PCAP), the AR polariser can only be applied to the top of the cover glass due to the sensor film.

WITHOUT OPTICAL BONDING

Cover plate

Moisture

Parallax problems with flexible cover

TFT panel

FEATURE

WITH OPTICAL BONDING

Air gap

Foam tape

No air gap

No moisture problems

Rugged assembly

TFT panel

Bonded cover glass / touch panel

Optical compound reduces internal / external reflections

Optical bonding ensures a clear view and increases contrast for clear visibility.

There are also quarter-wave polarisers.

These are designed to improve the viewing of TFT displays when wearing polarised lens sunglasses. TFT displays naturally output light in a single plane - if this is 90° out of sync with the viewer’s sunglasses, the display can be practically unreadable, appearing virtually black.

Relec Electronics has been working closely with partners to develop quarterwave retarder films which resolve this particular obstacle to viewing TFT displays.

Touch panel optimisation The company also has high-noiseimmunity touch-panel options, with models providing up to 32V/m noise immunity to ensure that exterior signals do not interfere with the display. This is particularly relevant for mission-critical displays in driver’s cabs or central control systems. High-noise-

immunity touch panels are also specified for use in medical, automotive and avionics equipment and systems.

To meet an application’s requirements, the touch-screen firmware can be tailored to the user’s specifications via a Graphical User Interface (GUI). In this way, a number of features can be defined, including, for example, the number of touch points. This is useful to reduce the fixed number of points on the original firmware or it can be used to increase the number, to allow for more gestures.

The GUI can also be used to determine touch sensitivity for optimal performance.

If the current level is too sensitive, it can produce ‘ghost’ touches, or the screen might be susceptible to a noisy environment. If, however, the installation is located behind a second piece of glass, the sensitivity needs to be increased, to maintain the level of performance.

The firmware can also be tailored to meet the installation mounting type (landscape, portrait, 180°) by rotating the axis of the display.

The input method is also implemented via firmware, for example, the click mode can be adjusted to either emulate a mouse or standard touch mode.

Rail Engineer | Issue 185 | July/August 2020

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FEATURE

Electrification AND THE environmental

CHALLENGE

PETER STANTON

L

eaving aside Covid-19, which is on everyone’s mind right now, the environment still sits high on the agenda, along with international concern on how to tackle the ‘climate emergency’.

Environmental studies have shown that transport has a significant impact on the environment. This can be reduced by using electrical energy that is largely derived from sustainable sources – and that means by using electric trains and trams (and trolley buses – remember them?)

To make this effective, and to reduce the carbon from vehicle exhausts and even diesel-powered trains, a modal shift is needed to an electrified railway. It doesn’t matter, in environmental terms, whether that electric power comes from an overhead distribution system or a third (or fourth) rail – it just needs to be electric.

Unfortunately, the United Kingdom has a relatively low proportion of electrified railway, compared to many other

Rail Engineer | Issue 185 | July/August 2020

countries, a situation that needs to be reversed as soon as possible if the UK is to meet its zero-carbon targets.

Studies by Network Rail and others have shown that, as widespread electrification proceeds, temporary and lessattractive energy sources could be used, such as battery or hydrogen traction. The existing and proposed bi-mode fleets of electric/diesel hybrids could also contribute, by spanning the gaps in the electrified railway as construction of a national contact system advances.

Chequered history The relative lack of electrified railway in the United Kingdom has arisen through a rather chequered history in traction power development. At the beginning of the twentieth century, there was much emphasis on electrification, often for suburban services and mainly with medium voltage DC. This rolled forward into proposals in the 1930s for significant mainline electrification, as recommended by the Weir report.

FEATURE Some design and construction moved forward, but was then halted by the Second World War, restarting in the late 1940s.

In the early 1950s, studies showed the preferred way forward was to utilise industrial-frequency supplies at high voltage with lighter weight contact system equipment.

Momentum then picked up, with proposals for electrifying the main north/south lines. Construction soon commenced, after some protype experimental installations in the North West.

The first stage was to electrify the West Coast route, but concerns over costs caused the scheme to be subject to intense scrutiny and the threat of abandonment.

British Railways reacted in a positive and effective way and the scheme was then rolled out between London and Birmingham. However, that’s where development stopped, although Scottish and London’s eastern suburban schemes advanced.

British Rail then undertook a complete rethink on design and construction philosophy and the government became convinced to allow the system to be completed to the main Scottish termini.

Network Rail OCR team wiring demonstration on the Windhoff wiring train at Long Marston.

The various energy crises in the 1970s led to comprehensive proposals to undertake wide-ranging electrification of the British railway system and this culminated in a major system-wide electrification strategy.

By the early 1980s, however, the political atmosphere was not sympathetic to rail as a transport technology, so the strategy was never enacted, although the energisation of some routes did continue, albeit at a piece by piece pace.

Environmental awareness grew and, by the end of the 20th century, there was renewed interest in electric traction, fuelled by awareness that, elsewhere in the world, railway electrification proceeded at a robust pace.

With a growing profile of public transport desirability and pressing environmental issues, the UK government looked at alternative ‘fuels’ and traction power arrangements. This culminated in fossil fuels falling out of favour and, in the new century’s second decade, the country seemed to accept that electrification was the way forward.

This resulted in a suddenly accelerated design and construction strategy, aiming to equip a large portion of the remaining non-electrified British railway network. A major attempt at countrywide mobilisation of resources followed but, in the light of problems with the Great Western electrification scheme, the entire new philosophy was abandoned, with a major switch to ordering bi-mode trains, fitted with both diesel and electric power units.

Scotland became an exemption here, moving electrification forward at an increasing speed and filling long awaited gaps in modern service provision. It can be said that this was because the programme was overseen by Transport Scotland, not the Department for Transport, so was not subject to departmental dithering and political interference to the same extent.

Even the electrification of the Midland main line from London to the Midlands was cut short part-way through Kettering and Corby.

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FEATURE Consultant’s view Rail Engineer met with Peter Dearman to discuss and review the situation, to look back at history while searching for solutions to rethink today’s electrification policy with a fresh approach.

Peter has been active in the railway industry for some considerable time, with his career almost completely allied to electrification engineering. He was formerly head of energy at Network Rail, before becoming head of electrification at SNCF-subsidiary Systra, electrification advisor with programme-management consultant Bechtel and then engineering director at Atkins. He is now an independent consultant.

He also has a passionate interest in the history of rail traction power supplies and contact systems, and thus is almost uniquely qualified to comment. With strong and positive views over railway electrification, Peter was able to look at the lessons of history with a view to learning from it and developing a fresh approach to plan for the future.

Revisiting that history, it is apparent that railway electrification today is presenting almost the same challenges that it did in the late British Rail era. The question is, what has changed?

The immediate answers are: » The volume of rail traffic is greater, and access is more limited; » Safety arrangements and requirements are (perhaps justifiably) more all-encompassing and onerous; » Project organisations are disproportionately large.

Series 2 OLE Liverpool to Manchester wiring.

However, on the other hand, we can ask what has NOT changed: » The hardware of electrification still consists of OLE (overhead line equipment), foundations, steel, smallpart steelwork and wires - they might look different but, in many ways, the modern equipment is, in fact, easier to construct; » There is also still the need for electrical supply equipment, switchgear, protection and control systems and transformers, but on a larger scale; » Work on track still requires manpower and plant, working in antisocial patterns of nights, weekends and bank-holidays.

The cost and time overruns experienced on the Great Western scheme received a great deal of (negative) publicity. To make valid comparisons, these need to be put into context.

Peter highlighted, firstly, that cost escalators can be estimated and normalised for inflation. Applying these to the cost of electrification hardware results in an estimation that, at worst, there is around a 20 per cent increase in today’s prices over the costs that British Rail faced in the past.

Looking at the sheer scale of the cost and time overruns in Control Period 5, these cannot be the result of the increased cost of the electrification hardware or the construction works, and therefore it must have been caused by other factors.

With his considerable experience in both the nationalised and privatised rail industry sectors, Peter has reviewed the history of approaches to the modernisation. There is no doubt that British Rail had strong leadership with

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a commitment to deliver. However, the problems and challenges that arose from the EML (Euston, Manchester and Liverpool) scheme promoted a major rethink. From that deliberation arose the RRR&E (Route Rationalisation, Resignal and Electrify) principle – a philosophy that protected the ability to manage electrification as a production line and so encouraged uniformity and enabled efficiency.

At that time, BR faced the challenges of modernising an outdated railway, configured for traditional goods traffic and steam traction, signalled by multiple small manual signal boxes. By the late BR schemes, notably ECML (East Coast main line), the railway had moved on to diesel traction and the end of that traditional goods traffic had allowed the removal of the Victorian infrastructure clutter, replaced by large power boxes with colour light signalling.

But the lessons had been learned and the spirit of RRR&E was followed.

All large-scale enabling works to track, bridges, and stations were completed before any OLE production build commenced. Maintaining that management of the project critical path, to protect the production efficiency of the OLE build, is a critical issue that Peter believes the industry needs to re-learn.

Privatisation of the British railway infrastructure management brought about the Railtrack Major Projects Division. This significantly changed the structure and course of project management in the rail industry. A philosophy of project management processes new to rail, led by personalities extremely experienced in project management in non-rail fields, was applied. However, it must be noted

FEATURE that the number of experienced rail industry engineers was low in the new organisation.

As the industry settled into its new order, the process of route modernisation continued, though this was not completely a Railtrack introduction, as West Coast Route Modernisation had been started under British Rail auspices.

The principle had also been piloted on the Chilterns but, of course, that was not an electrified railway. Peter’s view, however, is that, as time has advanced, the latest route modernisations (West Coast, Great Western, Edinburgh to Glasgow) have all failed to show any comprehension of, or any plan to interpret, update and apply, principles analogous to RRR&E. He highlights this as running parallel to the failure to see that cost efficiency is only possible by the application of manufacturing production principles.

Allied to these views, he also feels that the interpretation of CSM RA (Common Safety Method for Risk Assessment) is not mature, a major example being the excessive number of overline bridge reconstructions undertaken.

Expanding on that last thought, Peter suggested that a programme of electrification should: » Establish where bridges need intervention (analysis of available clearance following CSM RA principles); » ONLY those for which no positive CSM RA clearance case can be established are then scheduled for work intervention. » Generally, the intervention will be to apply recommended GLRT1210 clearances;

Structure renewals: Mk 3B OLE at Thrandeston embankment on the Great Eastern line, Dec 2008 - the project which won a Civil Engineering GeoTech award. » But, where the costs of full compliance are disproportionately high, CSM RA is used to define less-costly works to provide economic clearances; » Then, and only then, are the economic civil engineering interventions applied to the structure(s); » Finally, and only after all the above are complete, construct the OLE.

Conclusions The discussion was far ranging and in great depth but, in summary, Peter’s conclusion summarised the presentday situation as he pulled together his thoughts on how and where electrification of the British railway should proceed.

Overall, the cost of electrification in 2020 is demonstrably higher than it was in 1984. However, the same delta affects every aspect of rail infrastructure and electrification is not, in that respect, unique.

Analysis shows that the poor performance of electrification schemes in Control Period 5 cannot be attributed to the cost of electrification equipment, to the fundamental components or to the electrification system as a whole.

However, the failures of cost control and uncontrolled extension of programme can be viewed as deeprooted organisational, contractual and cultural mismatches which the industry is only now beginning to address.

With TDNS (Traction Decarbonisation Network Strategy) already in view on the horizon, and significant national focus on the environment, remedial action to the process of modernising the railway, with particular attention to electrification, could not be more pressing.

Not everything is totally downbeat, but examples from other railway organisations show the kind of performance that could be achieved. It would be possible to have deliberately avoided pointing out about all the good things we know, but there is a basic competence in the UK which is capable of successfully changing railway traction.

There are still technical issues, but these can be solved in the usual way as a rolling programme progresses.

The railway’s executive needs to provide solid leadership, contain collateral costs, such as bridges, and, most important of all, ensure project management organisations and processes match the needs of the production work. Otherwise, all of the other issues will have no need of attention, because electrification will not have any customers!

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DAVID SHIRRES

Re-engineering RAIL FREIGHT U

nlike most passenger train operators, rail freight must operate at a profit since it gets no government support. As it works to tight financial margins, it is difficult to justify large capital investment without a guaranteed market.

Class 57 locomotive acquired by ROG in October 2018. It is fitted with brake translation equipment and Dellner 12 couplers.

In such an environment, it is difficult to fund expensive, innovative rolling stock. Yet, our ‘Unlocking innovation online’ feature in the previous issue of Rail Engineer showed how the Rail Operations Group (ROG) was bucking this trend by investing in Class 769 bi-mode units as well as developing the Class 93 tri-mode locomotive concept.

ROG was formed in 2015 and currently specialises in the ad-hoc movement of rolling stock. At that time, thousands of new rail vehicles were about to be delivered. Moving these new trains from ports and factories to their depots was a significant market opportunity.

To move this high-value kit without delay, ROG acquired various locomotives and equipped them with a range of coupler types. It also focused on the train planning needed to make these moves at short notice.

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An early ROG innovation in 2016 was the fitment of miniaturised electrical brake translation equipment to their locomotives. This enabled the varying pressure in the locomotive’s brake pipe to control the electric brakes on the new trains they are towing.

Previously, this translation equipment was contained within translator vehicles which were difficult to obtain. As a result, in some cases, new trains

were dragged unbraked with a braked barrier vehicle at the rear, fed by a very long air pipe that ran through the train from the locomotive. This presented significant planning problems, as such trains were limited to 45mph and there were not many barrier vehicles to be had.

With new train procurement in the UK being done on a ‘boom and bust’ basis, the requirement for new train moves, and the associated movement of displaced stock, will be much reduced in a few years’ time. ROG is therefore looking to its future, for which it has developed two innovative concepts.

FEATURE High speed logistics The internet-driven increase in e-commerce has resulted in a 20 per cent increase in road van use over the past ten years. The five billion packages that are delivered in the UK each year make the express delivery market worth ÂŁ17 billion. ROG and its sister company, Orion, believe that rail can capture a share of this market and that the required investment to do so would only require rail to take a small percentage share.

As a result, Orion is developing a rail logistics network that will consist of around twenty stations and twelve ports or logistics terminals. These will be linked by trains offering unbeatable journey times. For example, Origin envisages a 5.5-hour journey time between London and Glasgow, compared with about ten hours for a lorry trip. The use of city-centre stations further increases the attractiveness of this service.

To date, rail has not been able to provide such a service due to the lack of suitable rolling stock.

Most UK rail freight is containerised intermodal cargo, which averages around 30 miles per hour.

What is needed is a go-anywhere train that can run at 100mph to passenger timings.

The Class 769 tri-mode units that have been developed by Porterbrook (issue 168, October 2018) meet this requirement. These are converted surplus four-car Class 319 units that originally ran on the Thameslink route and so were powered by either 25kV AC OLE or 750V DC third rail. The conversion adds a 390kW diesel alternator set to each of the two trailer coaches, driving the traction motors via the existing DC bus line. After losses, and the requirement to power auxiliary equipment, are considered, this gives the unit 550 kW of diesel power at the wheels. Although this is little more than half the unit’s electric traction power, it is sufficient to give the unit a balancing speed of 87mph on a level gradient.

As such goanywhere units are ideal for the proposed high-speed logistic service, ROG has ordered five Class 769s. ROG is also interested in acquiring Class 319 units which, with minor modifications to control circuitry, could work in multiple with the Class 769s. Karl envisages running a 12-car train with two Class 319 units and a single Class 769 unit. Such a train would run on electrified lines for most of its journey and use the Class 769 as a tractor unit off the wires, when it would run at a slow speed, say 40 or 50mph, for a short distance to its destination.

Two types of conversion are required before ROG can start its logistics service: Wabtec is converting the Class 319 units to Class 769 units and both types of units need to be repurposed to enable them to carry packages and light freight. The specification for this repurposing has yet to be finalised and will take account of the opinions of prospective customers. As part of this exercise, a unit is being fitted with various types of floor (roller, vinyl and a strengthened floor).

Proposed ROG highspeed logistics network.

Class 769 engine raft.

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Class 93 locomotive.

It had been expected that ROG would receive its first Class 769 unit in September. However, due to delays, it is now expected that the first unit will be delivered around the end of the year. This should enable a pilot service between London Gateway and Liverpool Street station to be introduced early in 2021, with the full logistics service launched a year later.

Orion’s delivery service will be supported by digital logistics technologies that will provide state-of-the-art customer service, such as real-time tracking. Various options are being considered for last-mile deliveries from citycentre stations, including the use of autonomous vehicles.

High speed freight ROG also has an innovative vision for locohauled freight, as chief executive officer Karl Watts advised Rail Engineer in a recent interview.

He felt that, currently, freight operating companies are “glued to Class 66 operations”.

Although the Class 66 was designed 25 years ago, it is a reliable machine which does its job well and, with the tight margins associated with rail freight operation, there is little incentive for freight companies to invest in modern locomotives, even though they have lower fuel and maintenance costs.

Yet, looking to the future, Karl believes there is a requirement for an advanced freight locomotive.

The decarbonisation agenda requires rail freight to reduce its CO2 emissions. Furthermore, the Class 66’s two-stroke engine fails to meet current particulate emission standards.

Reducing emissions requires a reduction of diesel running under the wires. However, providing an electrically powered freight locomotive that offers acceptable performance off the wires is a challenging requirement.

Another problem with freight traffic is its slow speed. When Freightliners (the wagons, not the company) were introduced in 1965, they ran at a maximum speed of 75mph, which was

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comparable with the speed of passenger trains of the time. Yet container trains and Class 66 locomotives still run at a 75mph maximum speed today. Pathing freight trains running on a busy rail network, on which passenger trains run at 100 or 125mph, is problematic. The rail network could accommodate more freight if it could run at higher speeds.

Fast rail freight would also support the decarbonisation requirement as a modal shift of freight to rail would reduce overall CO2 emissions. Covid-19 may have reduced rail traffic for now, but, in the future, a high-capacity rail network will have an essential part to play in decarbonising UK transport.

For these reasons, Karl believes that there is a requirement for a fast freight locomotive that is electric-powered under the wires but is self-powered away from them. The Stadler-built Class 88 is such an electro-diesel locomotive and is a development of the Class 68 diesel locomotive. These are operated by Direct Rail Services (DRS), which first acquired them in 2017 and 2014 respectively.

The Class 88 is a Stadler ‘UK-Dual’ locomotive.

It has a maximum speed of 100mph and a maximum power of 4,000kW under 25kV AC OLE and 700kW in diesel mode using a Euro IIIB emissions compliant Caterpillar C27 diesel engine. However, its power in diesel mode is only equivalent to that of a single Class 20 locomotive. Hence, for freight away from the wires, the Class 88 is only suitable for ‘last mile’ operations in sidings or slow-speed operation on freight-only branches.

Tri-mode power Karl explained how ROG has been in discussion with Stadler to develop the Class 93 locomotive, which will have main-line freight capability on non-electrified lines. This a development of the Class 88 locomotive with a more powerful diesel engine, a traction battery and an increased maximum speed of 110mph.

FEATURE The locomotive is described as a tri-mode as it has three different power sources.

However, it only has two modes of operation, electric and diesel/ battery hybrid. In electric mode, the batteries are charged when braking or from the transformer.

As the batteries use the space occupied by the braking resistors in the Class 88, when the batteries are fully charged, the locomotive has only its friction brake.

In diesel/battery hybrid mode, the batteries are charged both as the train brakes and by the diesel engine when it is not operating under full load. When the train accelerates, the batteries give it the extra power needed to get up to speed. This is a significant benefit as accelerating a freight train of over 1,000 tonnes up to its operating speed can take several minutes.

The Class 93 will have a six-cylinder Caterpillar C32 turbocharged engine, rated at 900kW at 1,800rpm, which meets the EU97/68 stage IIIB emission requirement. It has two Lithium Titanate Oxide liquidcooled battery packs, which have a rapid charge and discharge rate. These each have a 40kWh capacity with a peak power of 200kW. Thus, whilst the train is accelerating, the Class 93 will have a peak power of 1,300kW for up to ten minutes, which is almost twice that of a Class 88 in diesel mode.

As a result, the 86-tonne Class 93 is capable of hauling 1,500 tonnes on non-electrified routes and 2,500 tonnes on electrified routes. With a route availability (RA) of seven, it can be used on most of the rail network.

Both the Class 88 and Class 93 are Bo-Bo locomotives. DRS’s original intention was that the Class 68 should be a Co-Co locomotive, as the Class 66 is.

However, Stadler convinced DRS that modern traction electronic control would enable a fouraxle locomotive to haul a heavy freight train and was able to demonstrate that this was the case on the Velim test track.

With its ROG pedigree, it is not surprising that the Class 93 is also designed to haul passenger stock. For this, it has a variable height Dellner coupler and a three-step Westcode brake, in addition to its conventional twopipe air brake.

freight operations in which the commercial incentive is to maximise income by increasing train length, even though this increases running times.

He believes that the Class 93 could offer a more dynamic operation for modal freight, with an increased frequency of shorter trains running at higher speeds. This would also require faster container flats, for which ROG are also in discussions with various bodies to develop a high-speed freight bogie. In addition to being a more commercially attractive operating model, this would enable more freight trains to be run on a busy railway.

Clearly, ROG is an innovative company, particularly in respect of its Class 93 concept. It is always good to see railway engineering that delivers business benefits, and this is particularly true with the Class 93, which has the potential to revolutionise intermodal rail freight.

However, at a cost of around £4 million per locomotive, a Class 93 fleet requires a significant investment to realise these benefits. Perhaps for this reason, an order has yet to be placed for Class 93 production, even though the concept was first proposed in 2018. Although borrowing £10s of millions is far from straightforward, given its benefits, it is to be hoped that an order for the Class 93 can be placed soon, and Rail Engineer looks forward to seeing the first one in operation.

Phenomenal benefits Modelling the performance of a Class 93 locomotive has shown that it offers “phenomenal” business benefits.

For example, the running time of a 1,500-tonne freight train between Felixstowe and Mossend of 11 hours 9 minutes with a Class 66 locomotive would be reduced to 8 hours 32 minutes using a Class 93.

Such reductions in running time offer significant improvements in freight train utilisation. A further example is that a class 93 would enable a train to make two return trips a day between Thames Gateway and Corby.

The Class 93 also offers significant reduction in operating costs. As well as lower maintenance costs, it has a third of the fuel consumption of a Class 66. Furthermore, the 86-tonne Class 93 has lower track charges than the 130-tonne class 66.

Karl considers that the Class 93 will be a true go-anyway mixed-traffic locomotive, with the ability to haul fast passenger trains and freight trains of up to 2,500 tonnes on fully electrified routes. Moreover, he considers that it could change the business paradigm of intermodal rail

CLASS 93 GENERAL ARRANGEMENT 2

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Variable height Dellner coupler Traction Motor Blower Low voltage cabinet Pantograph AC cabinet

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Westcode translator panel Traction Battery Brake panel Inverter and Transformer cooling tower Power cabinet

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Generator Compressor 900kW Caterpillar C32 diesel engine Engine cooling tower

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Unlocking Innovation:

The Digital Railway CLIVE KESSELL

F

ollowing on from David Shirres’ article in issue 184 (May/June 2020), the Railway Industry Association staged a week-long webinar to explore how innovation can help the transition to a Digital Railway. Held online between 29 June and 3 July, the sessions explored various elements on introducing digital systems, but mainly concentrated on how the ERTMS project would roll out on the East Coast main line and other routes thereafter. Interesting views and challenges came across, but one thing is for certain, it will not be easy.

I first reported on the Digital Railway in September 2015, when the concept was to make all railway operations and business more efficient by the adoption of digital techniques. This proved too ambitious and failed to recognise the significant problems of implementation.

A second article appeared in January 2017, when the newly appointed David Waboso gave his more realistic view on the elements that would make a successful digital railway. ETCS featured prominently, but the progress made since then has not met expectations. In the same edition, Adrian Shooter outlined some innovative projects of the past, most of which were abandoned because of technical and delivery difficulties – the APT (Advanced Passenger Train) being the most prominent.

So, what is different now? The following commentary will hopefully give some answers.

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New structure Network Rail has long recognised that the digital railway would need a centralised strategy for implementation.

However, with its mainstream organisation now focussed on five Regions and 14 Routes, harmonising central and local interests will need the appropriate diplomacy.

Nick King is director of Network Rail’s Network Services group, which aims to pull together Route Services, Network Services and Systems Operations into a Technical Authority that will steer the introduction of digital technology.

The group needs highly skilled expertise and is likely to expand from the present 180 people to 1,500. It will include Network Rail Telecoms (NRT), seen as a key element in connecting it all together.

Six ‘pillars’ make up the group’s focus: I - Network strategy and operations II - Passenger interests

FEATURE

III - Freight interests IV - NRT V - Operations project delivery VI - Signalling innovations including testing and commissioning.

The Department for Transport (DfT) supports this model as a Sector Plan.

Improving track-worker safety and reducing trespassing are still important, as the recent tragic incidents such as Margam and Roade show. 10,000 people work on or near the track every day, but only 26 per cent of the tasks undertaken are completed with line blocks or additional protection.

16 per cent happen in red zones with unassisted look out facilities, 16 per cent are completed without the protection method being recorded.

On a railway which has 60 per cent higher track utilisation than most of Europe, a move towards intelligent infrastructure is long overdue. As one track engineer remarked: “Data, data everywhere, but not a drop to use.”

Whilst some of the benefits of a move to risk-based maintenance are being realised, infrastructure faults still cause massive delay. Using data streams for intelligent decision making, coupled with aerial (drone-based) surveys, could make a big difference.

Is the rail industry successful in introducing new technology? In general, the answer is NO. Many legacy data systems exist, for example TOPS and TRUST, but they have no clear owner, which prevents them being updated and acts as a deterrent to the adoption of more modern data formats.

Is there insufficient industry leadership, the so-called directing minds? An allindustry approach is required to specify what is needed. Technology must be kept up to date, with better use of the engineering elements, for instance using the signalling system to show how the track asset is conditioned. Maybe artificial intelligence (AI) will help, but data silos remain a big risk.

Digital Railway components Andrew Simmons, the chief systems engineer for Network Rail’s Digital Railway, has a background in signal engineering, but is now tasked with widening the signalling elements into fully digital command and control systems. He listed these as: » Safe separation of trains – ETCS » Train movement control – C-DAS » Traffic management » Telecoms & data – the NRT fibre and radio networks.

All need skills, capabilities and business change to successfully link into a Digital Railway Systems Authority, which has been a concept since 2017 and is now fully operational. But what is a Systems Authority? It is the body that will give a high-level steer but, beneath it, there has to be a: I - Technical Authority II - Design Authority III - Technical Systems Integrator IV - Rail Systems Integrator V - System Users Group.

A whole industry and whole systems approach is necessary for these to be

achieved and will lead to a whole life cost realisation plus safety and security enhancements.

Even with these in place, at implementation level there needs to be a Guiding Body to produce the technical strategy, an Assurance Function to carry out checks and balances, a Configurations Management to integrate other systems, an Issues Management to deal with emerging problems and a Requirements Management for verification and validation.

The overall Authority Governance will rest with Network Rail, the Rail Delivery Group and RSSB with input from train and freight operators (TOCs and FOCs), rolling stock leasing companies and the Network Rail routes. The plan is to bed the digital systems in on the ECML and trans-Pennine routes, then turn the results into RSSB standards.

One could be forgiven for commenting that this is interoperability in its ultimate form!

East Coast main line ETCS on the ECML will not be the first applications of this technology in the UK. The Cambrian line was converted as long ago as 2010, then came Thameslink with ATO superimposed on to it (another UK first) and the GWML being in the installation phase from Heathrow Airport to Paddington as an overlay to the lineside signals to cater for non-fitted trains. The ECML is thus the first mainline application where lineside signals will be removed.

Toufic Machnouk, Network Rail’s route programme director, explained the project and some of the challenges. ETCS will extend from London King’s Cross and Moorgate to Stoke tunnel, just short of Grantham, around 100 miles in length. It is essentially a renewals project, but capacity and performance gains will be made. In addition to Network Rail, other bodies involved include four TOCs, seven FOCs,

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The railway is integrating like never before. the supply chain, the trade unions, the government and the safety authorities.

The experience gained from previous UK projects will be taken into account, as will lessons learned from European countries – Denmark, Norway, Netherlands – plus also the National Air Traffic Services (NATS) project.

Success will be more about people than technology, with the partnership between track and train being crucial. The project will proceed in five tranches: 1. The Northern City line between Finsbury Park and Moorgate in London, this being a self-contained section mainly in tunnel; 2. Provision of ETCS as an overlay to the existing signalling, mainly for driver training; 3. Provision of a Traffic Management System; 4. Progressive roll out including train fitment; 5. Optimisation and clarification with eventual removal of lineside signals.

The biggest challenges are seen as: I - Retro-fitting the legacy fleet including on-track machines; II - Intelligent timetable development for both a high speed and mixed traffic railway; III - Business capability and response to change; IV - Credibility and affordability.

The government has signified its approval.

LNER perspective The main East Coast TOC has seen at least three changes of ownership in recent years. Paul Boyle, the head of ERTMS for LNER, has been in place through all this and has given talks at past conferences to tell of the TOC position. He must be gratified that, at long last, the project is underway.

The benefits of ETCS compared to conventional signalling have been regularly stated and research has shown some of the typical situations:

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» Emergency speed restrictions – trains will not slow down earlier than necessary, typically saving 24 seconds; » Approach to stop signals – a much faster approach will be permitted with an estimated gain of 45 seconds; » Late signal clearance – the DMI indication will come much earlier in all visibility conditions, estimated to be worth 1 minute 30 seconds; » Late level crossing closure (the ECML still has too many crossings) – more pronounced than signal clearance, worth 2 mins 25 secs; » Approach control for fast-to-slow line movements (modelled on Huntingdon) – much quicker slowing down profile calculated at saving 1 min 39 secs; » Train detection failure (track circuit fault) – train will be significantly slowed, then given a proceed instruction by radio verbal message without the train having to stop, resulting in an estimated time saving of 6 minutes 57 seconds compared to present operational practice.

ETCS simulators have been in use for some time (issue 145, Nov 2016) and the conditions outlined are obtained from consistent driver modelling.

Currently, the ECML suffers 44,000 minutes of unattributed delay in a year, affecting 3,950 trains with an average of 11 minutes delay per train.

Delivering these changes will need people at the core rather than technology. Business change managers are appointed for each TOC, including a User Design Working Group with trade union participation.

FEATURE

Fitting the fleet One lesson from the Cambrian early deployment was to try and avoid retrofitting existing rolling stock. Whilst all new trains since 2012 are supposed to have been built ETCS-ready (involving mainly passenger vehicles), Ewan Spencer from Siemens Mobility explained the challenge for freight. There are 745 locomotives in 20 classes (often with subclasses) having an age range of between 2 and 50 years. Multiple ownership across each class complicates the situation. The lack of information and drawings for the older locomotives does not help.

Certificate: PA05/04429

A survey of all classes is the starting point from which comes a: I - Concept design II - Preliminary design III - Final design IV - First in class fitment V - Laboratory test VI - Static test followed by test running on the RITC (Old Dalby test site) VII - Period of reliability running VIII - Fleet installation.

It looks complicated but some of these stages can be quite short if things go well.

As well as the ETCS equipment, including the balise reader and the

DMI, locomotives also need Doppler radar, a tachometer, brake and traction interfaces, a judicial recorder, speed displays and the installation materials.

Quite a shopping list.

Progress so far is that work on 16 out of the 20 classes is underway, with the Class 66 and 67 preliminary designs complete.

The Covid-19 pandemic has caused delays, as depot access is difficult.

What if it fails?

No matter how reliable a system, failures will always happen and signalling failures can be very disruptive.

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Rail Engineer covered the progress of DMWS (Degraded Mode Working System, previously known as Compass) on two occasions – in issues 129 (July 2015) and 162 (April 2018), the latter describing a preliminary proving trial on the ENIF Hertford loop site. The idea is to independently prove a train’s position and that the track ahead is safe to proceed, then to issue a movement instruction to the driver via the GSM-R radio.

Karl Butler-Garnham, the Programme Manager R&D in Network Rail, reported that a full operational trial site has been selected – Westbury to Castle Cary – and is planned for 2023. Many organisations will be involved including Altran, Siemens, Mott Macdonald, Ebeni, PA Consulting, RSSB and NCB (Network Certification Body), after which a wider deployment plan will be produced.

One could be forgiven for thinking that the process needs streamlining if a relatively simple and beneficial innovation like this takes eight years from concept to an operational trial.

Maybe this demonstrates the problem of implementing innovative ideas.

Rail Technical Strategy The Network Rail technical strategy, dating originally from 2012, is shortly to be refreshed and aligned with the Digital Railway. It will be more compelling and will take account of business need. The move forward from ETCS Level 2 to Level 3 will feature for capacity gains since it envisages moving block. However,

Level 3 is proving elusive across Europe, mainly because of train completeness assurance, so a Hybrid L3 version is being pursued. In addition, ATO as an overlay to Level 2, now in successful operation on Thameslink, will be part of the strategy.

This does mean the retention of track circuits and/or axle counters. A full description of Hybrid Level 3 was given in issue 151 (May 2017).

Another innovation in development is the ETCS Level 2 Limited Supervision Overlay. If trains are fitted with ETCS equipment, but are not operating in an ETCS fitted area, can the TPWS speed indications be used to interface with the driver’s ETCS DMI? When a TPWS overspeed condition is encountered, the train will brake, but the braking profile for that train is not known and the train may not stop before the red signal or within its overlap. By linking a TPWS ‘signal aspect sniffer’ to the ETCS on-board equipment, the braking profile becomes known and the train will stop more accurately, with incremental benefits being obtained.

A full prototype testing of both Hybrid L3 and L2 Limited Supervision will take place at the ENIF site in the period 2021/22.

Supply-chain perspectives Andrew Simmons described the benefits of the Hybrid variant, namely that passenger trains, where completeness is self-contained within the train data bus, can be given movement authorities for shorter block sections, thus allowing similar trains to operate with closer headways. Any trains not fitted with Level 3 equipment would continue to operate with Level 2 rules for safe distancing.

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Getting industry on board is crucial and both Andrew Stringer and Rob Morris from Siemens Mobility (based in Chippenham and with the pedigree of the former Westinghouse Brake and Signal Co) indicated the necessary commitment.

ETCS has been a long time coming, its first baseline being as far back as 1996.

What, however, does success look like?

How many more trains per hour can be operated? Will there be enough trains?

FEATURE Long-term deployment plan

Don’t overplay safety, since the UK is already the safest in Europe. The need to convince signal engineers of ETCS benefits is a fundamental factor! The ‘Sector Deal’ now in place includes the supply chain as much as the rail companies and Siemens, with others such as Alstom and Thales, will be major players. The portability of the programme should already be established through the EU interoperability rules.

The technology is proven, but will passengers actually notice? What will they be able to do that they cannot do now?

Will digital technology result in a genuine ‘walk up’ service?

The biggest problem with signalling projects is delivery, when access is crucial and increasingly hard to get and ever more expensive.

Alterations to existing signalling (stage works in old speak) is a particular challenge and new interlockings, coupled with point machines and signals brought up to modern standards, may be needed, even if only used for a couple of years or so.

The five-year delay to ERTMS is proving a real challenge for existing equipment. That said, industry recognises that ETCS is the only way forward.

The ever-decaying life of existing signalling assets is causing concern.

Network Rail plans for about 2,000 SEU (Signal Equivalent Unit) renewals each year, but the need often exceeds this, according to Pat McFadden, the Head of Technical Policy and Strategy at Network Rail. A budget of £830 million per year for renewals is in CP6, but life-extension work on existing equipment means this figure will be exceeded.

ETCS offers significant reductions in annual spend from 2035, but an increase in expenditure will be needed between now and then. Infrastructure spend will peak in 2027 and train fitment is a significant cost up to 2031. Only seven per cent of the fleet is fitted currently, with a further 40 per cent ready for fitment.

New vehicles will account for the rest.

3,000 SEU renewals per year is the maximum that can be achieved with digital signalling. In Europe, the cost of an SEU is £190,000, but the UK does not yet match this.

CP7 will see the run rate build up, early schemes being Peterborough – Ely – Kings Lynn, the Midland main line starting in the Bedford area and the WCML north of Warrington. Scotland will come later and will be subject to

Structural Precast for Railways

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separate government discussions. Wales is substantially equipped with modern conventional signalling, so will also be later on in the programme.

Martin Jones, the Chief Control, Command and Signalling Engineer for Network Rail, added comment on the £190,000 SEU cost, to be known as Target 190plus. The long-term plan shows 29 projects which need a standard architecture, with no bespoke solutions allowed. Access to industry will be required, which Network Rail is prepared to pay for.

The main benefits of 190plus will not be realised for 10+ years, so the industry must attempt to get some benefits earlier.

Changes to the planning system are envisaged: » GRIP 1-4 will require a better toolset to promote improved early planning; » GRIP 5-7 needs to produce a ‘synthetic environment’, such as testing with far less disruption; » A Commercial and Sourcing strategy to improve engagement with suppliers.

Those of us who can recall projects at the height of the 1950/60s modernisation plan, will remember that there was a very close relationship between BR and the signalling industry. It worked well and the delivery rate was remarkable.

The role of SMEs Just what can Small and Medium-sized Enterprises offer to the Digital Railway initiative? A number put forward ideas.

Lucy Prior from 3Squared considered that, whatever the digital railway turned out to be, the people who design and maintain the resultant systems will need enhanced training and re-assessment.

Getting front line staff to understand what it is all about is a challenge and specialist firms in this field can play a useful role.

Emily Kent from One Big Circle, a Bristol-based company with a background of video imaging, is working with the Signalling Innovations Group (see below) to provide video capture of trackside assets from any operational train. A project known as AIVR (Automated Intelligent Video Review) aims to transmit packets of data continually using integral onboard processing. Knowing the minuteby-minute state of the railway will be a vital input to future digital systems.

Martin Pocock from Oakland Group, a company specialising in data analytics and new to rail, considered how to reduce risk in major programmes. Re-stating ‘loads of data but no knowledge of how to handle it’, a combined architecture designed to work with real project data would bring real benefits. Projects often run late because project managers and engineers failed to see what was coming. The claim that an 82 per cent improvement in a nine-month project forecast must be worth investigating.

Simon Rodgers from Oodl considered that a digital railway could benefit from ‘patterns of machine learning’. A record of all that is happening on a train temperature, air conditioning, pollution, cleaning routine, ride quality and such like - would give prompts if any events or actions are missed. Oodl would be interested in seeking an industry partner to exploit its skills.

Stephen Bull from Ebini offered an independent safety assessment of innovative ideas to give an early indication of those that will succeed and those that should be abandoned. The company’s work with the DMWS system has been mentioned.

Contracts already exist with the main signalling suppliers under the Major Signalling Framework Agreements that

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provide an easier work progression for signalling renewals in the various Network Rail zones. Engaging SMEs to participate in these contracts is encouraged but is not always easy.

David Maddison from Alstom indicated that 20 per cent of its total spend goes direct to SMEs and a further 40 per cent via Tier 2 contractors. The route for greater SME involvement is to understand where the big companies are struggling and to suggest how a particular skill or product can help. Choosing the right time to engage is key to success.

The Network Rail Signalling Innovations Group, led by David Shipman, is not an SME but it does produce innovative ideas for the future of signalling and the digital railway. It has to ‘sell’ these ideas to other parts of Network Rail. A Rail Engineer article on the group’s work was published in October 2019 (issue 178).

Building a relationship with SMEs is seen as important, to analyse and value many of the ideas being put forward. This can assist the eventual placing of orders and provide ongoing monitoring on how well a product is developing and performing.

Network Rail invariably struggles to understand the value of an SME, with often a resistance to new ideas.

Can academia help?

Anyone who read my recent article on HS2 (issue 183, April 2020) will have noted that Leeds University is equipping itself with a comprehensive rail research department and Birmingham University is similarly geared up for rail innovation.

Jenny Illingworth spoke of the latter’s new Centre of Excellence for Digital Systems which is nearing completion.

Professor Clive Roberts and his Birmingham team are working jointly with the Thales Technical Services Group to create ‘digital twins’. The present uncoordinated practices, which lead to limited data sharing and different tools by different companies when working on new innovations, is a problem.

The digital twin idea, used successfully in the aerospace and maritime industries, creates a digital version alongside a real system that then allows a backward and forward movement of data between the two. Developments are undertaken firstly on the virtual system, then transferred to the real system with results and requirements fed back into the virtual system to make changes, and so forth.

The resulting data is useful for future decision making.

FEATURE

University research informs teaching – (left) operations simulation and (right) traffic management.

A digital twin is being worked up for the West Midlands Railway, covering Crewe to London plus all cross-city routes around Birmingham, which will provide simulations and a ‘synthetic’ environment model. The intention is to give confidence to Network Rail and bring other suppliers on board.

Robert Hopkin, the head of educational development at Birmingham University, emphasised the need for

training of specialist engineers and IT personnel by means of postgraduate courses. As well as MSc courses in Railway Systems Engineering & Integration and in Railway Control, shorter ones in digital leadership are being prepared, which will include overseas visits to gain a wider appreciation. Eight modules are envisaged, of which two will be available in early 2021.

In summary, RIA can regard this webinar as successful. Bringing sense to the digital railway concept was a challenge. Innovation takes many forms - it is as much about business processes as it is about new technology. Whilst the ECML project was the principal topic, novel ways of making rail operations more efficient were evident.

Above all, it is the pulling together of all parties involved that will determine the programme’s ultimate success.

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MARK PHILLIPS

Beeching Reversed: Reopening of the

Northumberland Line

Rail tour special SENRUG (South East Northumberland Rail User Group) at Ashington in 2008.

O

f the many closed lines that are currently being proposed or reviewed for possible reopening to passenger traffic, one that looks close to coming to fruition is the so-called Northumberland line. This is being actively promoted by Northumberland County Council, with AECOM (with SLC Rail) as scheme designers, working with Network Rail as the owners of the assets.

Interestingly, there are some special features in the characteristics of this project. It is not all about just reopening a passenger route. The authorities participating in the project are making sure that it will also be about integrating the reopened line with the needs of the local community from cultural, educational and business perspectives.

Context

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Stuart McNaughton, strategic transport manager for Northumberland County Council, explained that there are three key objectives to be achieved in the reinstatement of the passenger service in this area, over and beyond the obvious one of putting rail connectivity back into this part of south-east Northumberland, both for commuting and for travelling further afield.

In developing the detail of the design and characteristics of the new route and passenger services, the promoters are seeking to engage with the communities through which the line runs and to maximise collateral benefits.

These extra objectives are:

66766 with a work train at the site of Bedlington station in June 2020.

PHOTO: STEPHEN VEITCH

The line north-east of Newcastle-uponTyne running to Ashington and beyond was one of the closures ensuing from the Beeching Report. More correctly, it was not fully closed, but passenger traffic ceased in 1964. Since then, the line has continued in use for freight and still carries five trains daily in each direction.

The reopened line will be around 18 miles long with six new or refurbished stations at Ashington, Bedlington, Blyth Bebside, Newsham, Seaton Delaval and Northumberland Park. Services will then continue on to the existing stations of Manors and Newcastle Central.

The option of extending the service beyond Ashington to Woodhorn has been considered, but the costs of doing so are significant and this therefore remains a future possibility for the rail service.

Regarding access to the railway for people living in Blyth, unfortunately the railway line runs on the outskirts of the town but the location of the new station is well served by buses. Negotiations with the bus companies to do some slight rerouting to help create a viable bus rail interchange will be needed.

Specification and benefits of the reopened line

PHOTO: STEPHEN VEITCH

FEATURE

60021 crosses North Seaton viaduct with the 6N22 Tyne Dock to Lynemouth loaded biomass working on 10 July 2020. » Provision of better access to education, employment and housing development; » Creating a sustainable modal shift from road to rail; » Economic growth in the area.

At present, commuting time from Ashington into central Newcastle by bus or car is an hour or slightly over. The design criteria for the rail commute will be a journey time of 35 minutes or less, with a train frequency of 30 minutes as a minimum.

There is an aspiration to introduce low-carbon rolling stock for the new passenger services on the route. Rolling stock alternatives are being looked at and, certainly, there is a need to avoid diesel power - this type of rolling stock would do nothing to gain the benefits of transferring road traffic to rail and so alternatives such as battery powered rolling stock are being seriously considered. Northumberland County Council is in discussion with the market.

Various initiatives are under way to boost the economic value of the route, including exploring commercial possibilities adjacent to the various stations. The County Council is carrying out an “Economic Corridor Strategy Study”, employing Steer Economic Development to examine in detail the development opportunities along the route.

Developing the case for reopening AECOM and SLC Rail are working with Northumberland County Council to progress the scheme’s business case, engineering design and planning and consent processes necessary to support and validate the project.

The scheme is being developed in line with the government’s Department for Transport (DfT) RNEP (Rail Network Enhancement Pipeline) process. The scheme has now passed through the ‘Decision to Develop’ and the ‘Decision to Design’ stagegates and is now moving towards ‘Decision to Deliver’ and ‘Acceptance’.

In support of this process, the DfT’s business case process has been followed.

So far, both a Strategic Outline Business Case and an Outline Business Case have been produced, with the Full Business Case to be finalised once the final design and costs are confirmed.

From an engineering perspective, AECOM is currently undertaking the design for Approval in Principle, which is equivalent, in broad terms, to a GRIP (Network Rail’s Governance for Rail Investment Projects) 4 level of design. This will be followed by detailed design.

Infrastructure requirements The existing infrastructure on the route was originally built for passenger traffic as well as freight, but these would not now meet all the current standards. Currently, there are legacy signalling and control systems with four mechanical signal boxes from the late nineteenth century. There is a mix of signalling types, some features of which are not compatible with passenger trains.

The five or so trains a day in each direction are made up of those to and from Lynemouth power station and those taking fuel pellets imported from the USA for feeding Drax power station.

Currently the line has 24 level crossings of various types, ranging from private crossings up to Automatic Half Barrier and Manually Controlled Barrier types.

With the intensive train service of the future, it will be essential, for operational and safety reasons, to rationalise this inventory. It is planned that 10 will be upgraded to MSL or MCB-OD type, four will be closed and one will be replaced by a footbridge.

Track capacity needs increasing. Access to the main East Coast main line at Benton North is via a single lead junction and there will need to be some double tracking and provision of passing loops on the Northumberland line itself. Where possible, line speed will be increased to 65mph.

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FEATURE Kilborn Consulting is contracted to AECOM to carry out key elements of the detailed engineering preparation for the new infrastructure, including surveys, outline signalling, control systems and level crossing design, including signalling modifications and upgrades where appropriate.

Paul McSharry, managing director for Kilborn, said that the design policy will be one of evolution, not revolution, to achieve rationalisation and modernisation efficiently and economically. They will not be looking at this as a project to try out technical innovations, but will be working with Network Rail in a collaborative way. In particular, Network Rail’s local ASPRO (Asset Protection and Optimisation) team has been very supportive in development of the specification for the project.

Operational considerations Options for the control points for the line are still being looked at. For example, the signal boxes at Bedlington may or may not be redundant.

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One of the biggest challenges will be to ensure that there are adequate paths to accommodate the new services where they join the ECML at Manors and then on to Newcastle Central. It is believed that, when the passenger service from Ashington was last running in 1964, there were around a dozen main line trains each way on a typical day. Now there are 49!

Community engagement plans Bedlington, near the centre of the line to be reopened, has a proud history in relation to railways, being, amongst other things, both the birthplace of Daniel Gooch and a manufacturing centre for early rail forms and locomotives.

Northumberland County Council is working with Cadenza Transport Consulting to develop community engagement plans. The idea of these is to maximise the benefits to be gained from the reopening of the line. Three communities are identified - Arts, Academic and Business. Each of these represent very different groups of people

FEATURE x211411_NCC_A0_p2_sw.indd 7

Timescales Detailed design of all the new infrastructure requirements should be completed by mid 2021 and a Design and Build contract will be let soon after that.

The aspiration is for the line to open with the new passenger service by 2023/4.

Connected cities Rail Engineer was recently invited to attend a webinar hosted by ConnectedCities. This was one of a series of such events looking at rail regeneration schemes in several locations around the UK. The focus is on the wider societal benefits possible for communities adjacent to those schemes, apart from the obvious one of travel. The Tyne & Wear region is one of the locations which the organisation is currently studying.

ConnectedCities is working globally to foster ways of catering for increasing population growth in urban areas without detriment to the environment and, in fact, where and when possible, by enhancing living and working surroundings. It is doing this by being the catalyst in developments, alongside local authorities and community groups.

Ashington Station STATION LOCATION

POSSIBLE STATION LAYOUT

±

Key New Station Island Platform Approximate Ashington Station Boundary Northumberland Line

www.northumberland.gov.uk/line 28/08/2019 13:21

and the purpose of working with them individually is to build ownership of the railway.

For the Arts Engagement Plan, there has been public consultation exploring the history of the railway, with several people who can recall their previous use of the line. There are plans for a parallel walking and cycling trail, with encouragement to explore the route section by section, returning by train. Information boards and a sculpture trail are planned. Building pride in the line will be key.

For the Academic Engagement Plan, the intention is to work with pupils from primary age up to university level. How will the regeneration of the railway work for them? Ashington Academy may have a relationship with the railway which will promote careers. School children are going to be invited to make suggestions for the design of a nearby footbridge and 12 to 14-year-olds may well be asked to participate in teaching their peers about the dangers of the many level crossings and other potential hazards.

The aim of the Business Engagement Plan will be to create a coordinated approach across the region for business opportunities and to maximise the value of the railway to local businesses.

A key principle is to reduce an urban area’s dependency on travel by car.

This thinking is a shift change from a previous generation where a new urban development would be designed around car use, with Milton Keynes a classic example of that approach. This next generation of urban development should be founded on travel by rail, bus or tram, with increased walking and cycling opportunities.

A connected city is a grouping of moderately sized settlements that are not car dependent but have good public transport connections that link their town centres within 15 minutes. These towns then link to form the connected city with the ethos being all about liveable neighbourhoods, socially equitable, within 15 minutes walking distance of a station.

On a smaller scale, a ‘Pedshed’ is defined as an area within a one-kilometre radius of these towns’ railway stations.

Future development of housing and commercial, educational and recreational facilities would, as much as possible, be confined to within the Pedshed areas. In turn, this would mean that a significant share of travel within each town is possible on foot or cycle. For journeys outside that town to one of the others within the connected city, a walk or cycle ride of 15 minutes or less to the station coupled with a frequent rail service would be the norm.

The inhabitants across the overall connected city would be able to share facilities not resourceable by the individual towns, such as hospitals, theatres, recreational and educational centres and all easily accessible whilst, at the same time, maintaining significant green belts between the towns and green spaces within the towns.

ConnectedCities is currently very active in promoting its approach to urban planning. There is a major conference “Metroisation of the Railways: ConnectedCities” being held at Euston, London, in October, at which Network Rail chairman Sir Peter Hendy will be the keynote speaker.

Rail Engineer believes that we will soon be learning more of this philosophy, which could well prove to be a powerful element in building the case for individual route reopenings, new lines or enhancements to the services on existing railways.

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Cleaning THE RAIL HEAD MALCOM DOBELL

R

ail Engineer has often written about the problems of low adhesion caused by, inter alia, leaf debris rolled into the railhead. As a reminder, dry leaf debris can cause wrong-side track circuit failures and, when wet, can lead to very low wheel-rail friction levels.

A coefficient of friction of approximately 0.2 will allow trains to brake normally, but wet leaf debris firmly rolled into the rail can deliver an exceptionally low coefficient of friction in the order of 0.01.

To put this in context, the coefficient of friction in a well-lubricated car engine is circa 0.05.

Every Autumn, Network Rail runs Rail Head Treatment Trains (RHTT) to clean leaf debris from the rails. These trains blast the leaf debris, which by now has been firmly rolled onto the rail head by passing trains, with water jets at between 1,000 and 1,500 bar and then deposit sandite - sand with some ground metallic material suspended in a sticky paste.

These trains carry a very large quantity of water and sandite, are very effective, but also use capacity on the network.

Are there better techniques for cleaning the rails? Could they be deployed on service trains to avoid the loss of capacity? This is something that the Adhesion Research Group (a sub-group of RSSB’s Vehicle Track System Interface Committee) has been researching for some time. Four alternative methods were presented in a recent webinar hosted by RSSB, and the number of questions asked after the presentations was testament to the interest in the topic.

Four techniques were presented: dry ice, plasma, laser and, lastly, a very surprising solution, given that conventional wisdom says water and leaves are part of the problem, not the solution - improved braking through controlled water addition.

Dry ice Professor Roger Lewis from Sheffield University described the use of dry ice (solid carbon dioxide CO2) pellets to clean the rail. The principle is similar to the sand or soda blasting used to clean corroded steel; compressed air and the kinetic energy of the pellets bombard the contamination, although in this case, the thermal shock of the cold pellets makes the leaf film more brittle and the sudden expansion of the CO2 gas aids the removal of the leaf film.

It is useful to recall that CO2 does not exist as a liquid at atmospheric pressure, transitioning from solid to gas or vice versa without a liquid state. The supersonic compressed air deals with liquids/moisture and the pellets deal with solid matter. The effect is merely on the surface of the rail and cooling of the rail is virtually non-existent.

Even with the treatment train moving 16km/h, the rail head is

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FEATURE with a DMU delivered results on the cleaned rail that were at least as good as those on dry rail.

Roger concluded that cryogenic cleaning effectively removes oxide and leaf contamination from rails. It is a flexible technology that can be used manually, on a trolley or on an RRV. Next steps include testing leaf clearing and braking at higher speed. This might include tests using University of Huddersfield’s full-scale wheel/rail HAROLD rig, followed by trials on Tyne and Wear Metro’s RHTT with the aim of optimising performance of the dry ice system for RHTTs. exposed to the jet for only around 0.005 seconds. There is also no impact on cracks, insulated block joint end posts, ballast (allowing use on switches and crossings) and on the polymer around embedded rail.

Roger said that food grade dry ice could be delivered to depots as pellets (costing about £1/kg), made in depot or made on board the train. He added that the CO2 does not add to the carbon footprint as it is a captured as a by-product of other processes.

The concept was first tested using a roadrail vehicle (RRV) in the Sheffield Supertram depot. This delivered promising results,

leading to trials on five different Network Rail routes around Oban, Squires Gate and Knighton (passenger) and Deepcar and Sutton Park (freight).

As an example, at Oban, the test site ran from Oban depot (next to Oban station) to just before Connel. On average, there were two cleaning RRV visits per day and they cleaned just under six miles of track, with extensive rail swab measurements being taken before and after blasting; double the distance would have been possible without the measurements.

These trials consistently delivered bright rail heads, free from leaf film and, outside the running band, corrosion. Brake tests

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He paid tribute to his collaborators: British Steel, Metallisation, Microwave Technologies Consulting, Industrial Microwave Systems, The National Physical Laboratory and Knorr Bremse.

Clean.

There is also a plan to run a season long (10 week) cleaning trial on the West Highland line in Autumn 2020, to show the reliability of the RRV mounted system.

Finally, Roger wants to carry out more work to demonstrate the viability of fitting the system to passenger trains, reducing the effect on line capacity of using dedicated RHTTs.

Plasma Julian Swan, co-founder and engineering director of the Imagination Factory, discussed clearing leaves using a zerocontact electrical plasma jet. This produces an intense but focussed energy ‘beam’ using electricity and compressed gas and no other consumable materials.

As plasma is often used for cutting metals up to 150mm thick, the challenge is therefore to clear the leaves without harming the track, requiring a good control system. Turning off the plasma at slow speeds or when stationary also helps!

Contaminated.

After successful laboratory trials, a demonstrator was installed and tested on a container flat wagon. This delivered further confidence in the system and led to a prototype using a road-rail vehicle towing a custom road-rail trailer.

The photographs comparing the rail contamination before and after being cleaned demonstrate the effectiveness of the system after one pass. Julian said the results are cumulative, with any residual contamination being removed on subsequent passes of the plasma jet.

As one might expect, the efficacy of the system depends both on the power of the plasma jet and the speed of the train. For a given speed, a 25kW plasma jet delivers “pretty clean” rail after one pass and “virtually clean” rail after two passes. In comparison, a 15kW jet takes four passes to deliver virtually clean rail.

Julian illustrated how the system could be applied to a range of scenarios, being deployed from RRVs at <10 mph, high speed RHTTs, passenger and freight trains at >60 mph.

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The Laser Train Ben and Harm Medendorp of Laser Precision Solutions (LPS) presented their solution - cleaning the rails with lasers using the Pulsed Laser Ablation technique.

The use of laser technology was first put on rails two decades ago, having been trialled on Railtrack infrastructure under the name Laserthor in 1997. LPS started work in 2016 with the usual laboratory and prototype testing, but, since 2018, the company has been working with the Long Island Railroad (LIRR, part of the Metropolitan Transportation Authority of New York) to help it solve its leaf contamination problems.

In 2018, LPS demonstrated successful rail cleaning, delivering three times higher adhesion after one pass of the laser at 12mph, against a target of 9mph.

This convinced LIRR to commission LPS to produce a fully operational prototype, capable of operation from a non-passenger train at 25mph. This was deployed for 12 hours a day in autumn 2019 over extensive parts of the LIRR network prone to low adhesion. A reliability of 99 per cent was achieved.

LaserTrain

100% clean, dry and high traction railhead after one pass

BEFORE

AFTER

LaserTrain: Service-proven, ready to clean your railway at 20 â&#x20AC;&#x201C; 40 â&#x20AC;&#x201C; 60 mph 100% clean, dry and high traction railhead after one pass Fully autonomous, no operator required Operates in any weather Environmentally friendly, 100% electric, <80 kW power consumption Continuous cleaning, short daily inspection only

ben.medendorp@lasertribology.com www.laserprecisionsolutions.com

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FEATURE The results were impressive. Compared with 2018, LIRR reported a 17 per cent reduction in low adhesion events on the whole network and 65 per cent reduction on the lines where LaserTrain operated.

There was a two per cent improvement in punctuality, 65 per cent fewer late trains due to “weather”, 32 per cent fewer short trains and 48 per cent fewer cancellations (the latter two points due to fewer units awaiting wheel flat repairs).

With fuel or any other source of energy as the only required input (35kW system consumption), the LaserTrain, logistically, is easy to implement.

The next stage is to scale the system so that it can operate at line speed (approximately 60 to 70mph). The required laser technology is ready and LPS is looking for a partner to put it to good use.

Water-Trak At first sight, it seems odd to add water to slippery rails, but, of course, that is exactly what the RHTT does, leading to the questions “how much” and “when”?

John Cooke of CoCatalyst and Simon Barnard of SCB Associates explained: “The role of water in creating low adhesion is now well understood. We know that a dry track will deliver the highest level of adhesion. Wet track, while having a lower level of adhesion, will still give acceptable braking performance.

When a critical amount of water (microlitres per metre) is present on the railhead together with contaminants (such as compressed leaf matter or iron oxides) the adhesion value can reduce radically (down to 0.01 to 0.02) resulting in very poor braking and traction. Water-Trak aims to move the railhead away from this highly undesirable condition by adding water.”

LaserTrain installation.

Introducing between 1ml/metre and 4ml/metre of water into the ‘nip’ between the wheel and the rail is enough to deliver this effect. Using Huddersfield’s HAROLD rig, a test of braking on a leaf layer led to significant wheel slide, with WSP (wheel slide protection) activity lasting for over 30 seconds. When water was introduced, the duration of WSP activity reduced by nearly two thirds. In addition, the tests results showed a significant improvement in wheel and track cleaning, indicating the potential of Water-Trak as a rail head treatment solution.

The speakers said that the current water system has a capacity of over 200 litres for both rails, giving a total dispense time of over 30 minutes. One system would be provided at each end of fixed formation trains. If water is delivered only on WSP activation, they estimated that the water would last for 1-2 weeks of operation, depending on the adhesion encountered by the train. If it was decided that there is a cleaning benefit to be derived from delivering water every time a train brakes, then the 200 litres of water would be sufficient for more than one day’s operation.

As to effectiveness in combination with sanding, a study by the University of Sheffield has shown that sanding performance is significantly improved when delivered onto a wet track; water helps to retain more sand on the rail.

Water-Trak delivers water to the leading axle of the train so pre-wets the rail ahead of sand application. As the water does not interfere with, and may even enhance, the performance of track circuits, it also extends the operating envelope of low adhesion mitigation - it can work down to zero speed and in all locations, including points and crossings.

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John told Rail Engineer that it is not yet clear if slip between the wheel and rail due to braking is key to the removal of contaminants. One possibility is that water softens the leaf layer, allowing the mechanical action of the wheel rolling on the rail, together with the high pressures generated, to accelerate its removal, remembering that parts of the contact patch will be experiencing creep due to wheel-rail deformation even when the wheel is just rolling on the rail. He added that CoCatalyst plans to run some further tests in which water is added without braking to explore this phenomenon.

John also acknowledged that they have more work to do to make the system suitable for freezing conditions!

In summary, this is a simple, low cost, low risk system that can improve traction and braking for following trains, so the benefits of fitting a lot of trains is cumulative.

Conclusion The four techniques presented here have all demonstrated that they can effectively clean leaves off the rails. They are all at different levels of development - some have a degree of practical experience in improving adhesion on operating railways, whereas others have yet to emerge from the laboratory.

As always with these R&D projects, Rail Engineer will return to the topic as the projects progress.

Note: for more information on the plasma and laser processes, an examination of the Wikipedia articles on plasma cutting and laser ablation outlines some of the science.

Thanks to Paul Gray, Giulia Lorenzini and Ben Altman of RSSB, together with the presenters, for their help in preparing this article.

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