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A low cost interlocking has gained acceptance – but not the one Railtrack first thought of.
For a couple of years, I have had much fun at conferences on Railtrack's acceptance process pointing out that the Westinghouse WestRace vital safety interlocking, deemed good enough for radio transmission based Automatic Train Protection in Australia and the London Underground, was acceptable only for level crossings on Railtrack. On top of which, Westinghouse was unable to win one of Raikltrack's Signalling Partnership Projects aimed at introducing low cost electronic interlockings from other railways.
You will recall that the two pilot schemes that were let went to CSEE and Vaughan Harmon, both using simple vital safety processor interlockings already in service in the United States . In the event, CSEE's £13million contract for the Nuneaton-Peterborough fell by the wayside (something finally admitted by Railtrack in last month's Modern Railways), while Vaughan Harmon is still working up acceptance for the Norwich-Cromer branch now due for completion later this year at double the cost first thought of.
Meanwhile, Westinghouse kept on grafting away at the WestRace Railtrack safety case as a self-funded venture, taking my periodic ribbing with a tight lipped smile. And on 10 April this year Railtrack Scotland commissioned the first non SSI electronic interlocking on the UK main line network at Nairn, near Inverness . Not with one of the whizzo/cheapo pocket interlockings into which it has poured money, but using WestRace.
WestRace is now controlling the points at each end of the passing loop at Nairn station, where the vital interlocking is combined with a Westinghouse WestCad PC based control desk in the station building.
This replaces two manual signalboxes, one at each end of the passing loop. The local signalman used a bicycle to travel between these boxes: when a jubilant Westinghouse chum phoned with the news of the WestRace commissioning, the gnomic opening message was ‘The Nairn signalman's bike can go to a museum'.
Railtrack is treating Nairn as a pilot scheme in safety acceptance terms. Westinghouse will continue to bid WestRace for similar small schemes as they come up but, initially, each installation will be subject to a supplementary safety case. Once sufficient service experience has been acquired the interlocking will be given generic acceptance.
Service experience is a feature of a growing pragmatism in Railtrack safety approvals. For example, the recent extension of the safety case for the Class 465 electric multiple unit took into account five years safe operation.
Anywhere but on our disfunctional railway you would expect acceptance to give a manufacturer a commercial edge. But I fully expect Railtrack to continue with their ‘not if it's invented here' policy of favouring foreign kit.
And there's good news for acceptance on the Adtranz Signal front too. In the company's supplement in last month's magazine, I mentioned that Adtranz was pioneering ‘cross acceptance' for the application of its Ebilock interlocking on Railtrack.
In the case of an interlocking, cross acceptance means that existing safety acceptance from a recognised body is endorsed by Railtrack, rather than the manufacturer having to jump through all the same hurdles a second time for the Railtrack Infrastructure System Review Panel (ISRP). Adtranz was putting forward acceptance of Ebilock's safety principles and architecture by the German railway safety agency EBA.
So, more jubilation, by e-mail this time, with the news that at the ISRP hearing on 18 April Adtranz had it's Ebilock IPU950 cross-acceptance safety case endorsed. In other words, the safety principles and system
architecture of the Ebilock interlocking have bee accepted for use on the Railtrack infrastructure.
Of course joy was constrained. There is some way to go before Adtranz presents the full safety case incorporating British signalling principles, but this the first big hurdle has been overcome.
And Adtranz Signal is, significantly, making Ebilock compatible with existing lineside signalling equipment, such as points motors and track circuits, rather than requiring Railtrack to buy a total package. This is s shrewd move and should justify the time in preparing the safety case for the necessary interfaces.