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Railtrack has bitten the bullet on Computer Based Interlock – now it's over to Network Rail
No sooner had I put last month's column to bed, reporting Siemens' expectation that the Dorset coast resignalling would be commissioned in October, although the schedule was ‘tight', than a press release arrived fro Siemens announcing a ‘revised implementation strategy'. The new strategy will see the SIMIS-W Computer Based Interlocking (CBI) installed as planned but it will now operate, off-line, in ‘shadow' mode.
According to Mike Stubbs, general manager, of Siemens Transportation Systems' main line signalling and control business, the Dorset Coast Re-Signalling Alliance (Railtrack Southern Region, Siemens Transportation Systems, Interserve Rail and WS Atkins Rail) is nearing the end of a four week review aimed at developing a robust programme to confirm a new commissioning date ‘in the New Year'.
Siemens attributed the slippage to the effects of the latest Railway Group Standard for axle counters, particularly the need to replace track circuit track-clip protection with radio, plus delays in safety acceptance. During shadow mode operation, the installation will be used for on-site testing and also provide additional ‘practical' training time for the signallers and maintenance staff.
Shortly after this announcement Railtrack finally woke up to the reality, reported at nauseam in this column, that its signalling policy based on third and fourth generation CBIs with everything was a dead parrot. Note the generation qualification, which is a reminder that Solid State Interlocking is a first generation CBI and not some blind alley of the evolutionary ladder.
At a Railtrack Board meeting in July, Technical Director Richard Middleton declared a two-month moratorium on further development of proposed signalling schemes based on new generation CBIs. Informed Sources report that the intent of the moratorium is to give Railtrack time to assess progress and find out ‘what works and what doesn't'.
Of course the original three pilot schemes Manchester South (Ansaldo), Horsham (Bombardier) and Siemens were meant to do just this. But the evaluation could be either very difficult or quite easy.
With commissioning of Manchester South postponed sine die and Bombardier's CBI no longer in the frame for Thameslink 2000 (Informed Sources last month), Siemens looked the likeliest winner before the Dorset could deferment.
Meanwhile SSI schemes like West Anglia Route Modernisation (WARM) are rolling out smoothly, as are SSI installations around the world. And crafty old Westinghouse is going to be offering what is, in effect SSI NT (sorry Microsoft) with it Westlock CBI which ports SSI software and backwards compatible communications capabilities onto a modern vital safety platform.
So, the difficult option is to choose one of the three pilot technologies. The easy way is to continue specifying SSI, which is perfectly capable, as it should be, given that it was optimised for the sort of signalling schemes we have in this country. Meanwhile the pilots roll on and Westlock may, or may not, become a contender.
Anyway, when Network Rail takes over Railtrack, it will need to develop its own signalling strategy . From the make up of the new Network Rail board I would expect a conservative approach.