stephen rp
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- Joined
- 25 Jun 2016
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- 191
There was an accident in the Manchester area on the DC electrified lines where a signalman discovered that it was possible to defeat a timeout on some points by using a table knife or a Bardic lamp or some other handy metal object to bridge a set of contacts which were exposed when the slider for a signal on the route was pulled out, and so speed up operations. Until one night when he sped them up a little too much and ended up bringing them to a complete stop. ISTR the report being unwarrantedly hesitant over the idea of shrouding the contacts so they were no longer exposed, because on some patterns of frame it was difficult, while I was thinking the design was faulty for exposing them in any case simply because they might get bridged accidentally (which I think might possibly have been how the vuln was discovered in the first place).
Yes this was the accident at Audenshaw Junction (then controlled from the power frame in Stockport Junction (Guide Bridge) Box, on the evening of 20 May 1970. It was caused by the signalman interfering with the interlocking behind the frame.
That was a fatal accident. I was in the Manchester Division press office the next day. A reporter phoned to say that a railwayman on the train said he heard the points opening under the train. I said they were safety devices to prevent that, but indeed the signalman was shorting the track circuit locking the points (no physical bar), and had been doing it often so as not to wait for the TC to clear before switching the points for the next train. This time one bogie went straight on, the rear bogie went the other, and the coach went sideways into a bridge. The signalman went to prison for manslaughter.