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shavings
crossings
46 | the rail engineer | august 2011
level crossings
disposal and recycling are two of W aste the major challenges facing businesses today. With strict controls backed up by legislation, there is no escaping the problem. However, the old saying “there is nothing new under the sun” applies to waste disposal as much as anything else. 35 years ago a tyre re-treading business in Bavaria had the same problem. Before re-treading the original tread must be skimmed off so that virgin rubber can be vulcanised onto the old tyre carcass. Re-treading was going very well, but the mountain of rubber shavings was increasing by the day. What could be done with this mass of original rubber?
Smooth passage Natural rubber is a wonderful material. Without its resilience and strength transport would be very different. Today’s roads would not last long under lorries with solid tyres. Rubber absorbs most of the humps and bumps at the interface between wheel and road. So when an engineer from Kraiburg, that Bavarian tyre company with the waste problem, noticed how bumpy railway level crossings could be, it set him thinking. Couldn’t rubber be used to smooth the passage between wheel and railway? It would absorb much of the shock of heavy traffic bumping onto level crossings and thereby protect the geometry of the track. What would be needed were flat rubber panels to fit into the track. Kraiburg already had the expertise to vulcanise all those waste rubber shavings into interlocking panels which could be tied together with steel rods to make large flat areas of rubber. The panels should prove to be almost indestructible and relatively easy to work with. The rubber vulcanising process involves heat and pressure so a large heated press was installed, tooling designed and rubber level crossings were born. They were christened STRAIL, ST for street and - you can guess the rest.
First crossing In 1976 the first STRAIL rubber level crossing was installed at Recklinghausen in the Ruhr area of Germany. DB (Deutsche Bundesbahn at the time) and road users were most impressed and more STRAIL crossings were ordered. Since then, the story has been one of improvement and expansion. In 1993 the entire Oxberg bridge in Sweden was decked with STRAIL panels and, in the same year, a very hard corundum anti-skid surface was introduced. 1997 saw the introduction of pedeSTRAIL, a light weight system for pedestrians, and in the same year 1,270 square metres of STRAIL was installed in the marshalling yards at Wels in Austria- a record area of rubber surface. More exports followed to Finland, New Zealand, Argentina, Hong Kong and 46 other countries around the world. STRAIL rubber level crossings enable road traffic to cross railway lines quietly, comfortably and safely.
Arrangement Standard STRAIL level crossings are made up of full depth rubber panels weighing about 130 kg each. They protect the geometry of the railway track from the impact of heavy traffic and may be installed and removed easily for tamping and other track maintenance. The corundumimpregnated rubber surface gives road wheels a good grip and has a long service life. The rubber insulates one rail from the other, and also reduces noise nuisance by absorbing vibration within the rails. When installed, the individual panels span from sleeper to sleeper. They are supported throughout, resting on the sleepers and the ballast. Across the track they are shaped to slip under the rail head. Along it they are both interlocked with a tongue and groove connection and held together by high tensile steel rods running the entire width of the road. Thus it is virtually impossible to dislodge an individual panel.