32 | the rail engineer | february 2013
The heart of the signalling system is one new Smartlock secondgeneration solid state interlocking (SSI) unit provided at Rugby SCC covering four interlocking areas. Such is the enhanced computing power of these new units that it is only running at 50% of its capacity and there is potential to transfer the Milton Keynes area onto this (itself controlled from a traditional SSI since 2009). Linking the Bletchley outside equipment to the Rugby SCC uses existing Marconisupplied fibre-based transmission equipment installed earlier for the WCML route modernisation but with the diverse path being provided by the Network Rail fixed telecom network (FTN) which itself gives full diverse routing to protect against any fault occurring on one of the transmission legs. The FTN has replaced previously rented BT Megastream circuits. The commissioning was successfully achieved requiring 3,500 shifts and 40,000 man hours over the nine days of work. The fast lines were reopened at 04:30 on 27 December so as to allow a train service to operate for the important post-Christmas sales traffic. The slow lines were given back
feature
at 04:30 on 31 December and the railway will remain so configured until Easter.
On-going work With the re-signalling essentially completed and Bletchley PSB closed, there remains some critical track works to accomplish leading up the Easter 2013 Stage 7 commissioning phase. Reconnecting the Bedford line platforms to the up slow via a rationalised layout will provide a turnback facility on platform 5 for trains coming from Euston as well as restoring access to the carriage sidings from the south end. Work which commenced at Christmas to extend platforms 4 and 5 to accommodate 12-car trains will also be completed. The second relief line will be brought into use thus giving a double track loop for trains
requiring time to do crew changeover or hot axle box examinations without obstructing the main running lines. All work will be done within a 40-hour blockade over the Easter period. In the longer term, the proposed East West route from Oxford to Bedford and the Chiltern Railways proposal for an Aylesbury to Milton Keynes service will pass through the Bletchley area. The track and signalling is now in place to support these proposed services but the provision of new high level platforms will be an additional civil engineering challenge. Thus, whilst the WCML will be fully modernised with the last remaining 1960s’ signalling replaced at its southern end, there will continue to be works in the Bletchley vicinity for some time to come.