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#41
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In message . li, at
15:24:48 on Sat, 11 Sep 2010, Tom Anderson remarked: If we accept that stopping at a red is an acceptable part of the safety mechanism, why can't we also accept that stopping at the absence of a green, or the absence of any signal, is? Which goes back to the route knowledge people have dismissed a bit prematurely, earlier in the thread. Anyway, if a train has come out of the platform at the top, it's a bit obvious that if should be taking the x-over to get to the westbound track. http://goo.gl/maps/HuzB And it's only about 300 metres to West Ham station, so the other train must have been well west of there (maybe at Bromley-by-Bow station?). -- Roland Perry |
#42
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![]() "Alan Ben It" wrote in message ... It was the equipment that was faulty.The points moved when they shouldn't have. The failsafe of having points set and locked with a green signal (in this instance) failed.. Presumably the fact that the Plaistow bay was in normal passenger use by Friday (or earlier - that's when I saw it in normal use) suggests that whatever the fault actually was it was immediately fixable. Anything at all unpredictable and trains still wouldn't be running ... However it did occur to me that they are still some way through the installation of the new central turnback siding between West Ham and Plaistow. Presumably that will be requiring significant changes to the interlocking in the whole area. I believe that it will become the normal reversing point for short workings, ie pax will be tipped out at West Ham, but it is also obvious from the installed track layout that it will be accessible from both ends - so there are at least 6 new sets of points in the area between the two stations. But, IF the final design allows for entry to the central turnback siding from the Plaistow bay, I'd be looking at the stage they'd got to in the modifications... (I am not a signalling engineer though, corrections welcome...) Paul S |
#44
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![]() wrote in message ... Good grief! The bay exit even has a sand drag to protect it and they manage this error! The sand drag is to stop a train attempting to leave the bay siding onto the eastbound track though, it doesn't protect the crossover points, which are the third and fourth of four sets of points over which the train would travel from the bay to the westbound line. Paul S |
#45
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#46
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#47
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In article , ] (Steve
Fitzgerald) wrote: In message , writes I tentatively think this focus on the lack of signals is a bit misleading. Ultimately, all safety on non-ATO lines depends on drivers correctly responding to signals (barring tripcocks - am i right i thinking these are only present at a fraction of signals?). If we accept that stopping at a red is an acceptable part of the safety mechanism, why can't we also accept that stopping at the absence of a green, or the absence of any signal, is? Tripcocks are present at all home signals on LUL lines. You meant to say: Tripcocks are present at all stop signals on LUL lines. Didn't you? Yes. I wondered whether I'd got it wrong when I wrote it. I meant to exclude distant signals. -- Colin Rosenstiel |
#48
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On Sat, 11 Sep 2010, Steve Fitzgerald wrote:
In message , writes I tentatively think this focus on the lack of signals is a bit misleading. Ultimately, all safety on non-ATO lines depends on drivers correctly responding to signals (barring tripcocks - am i right i thinking these are only present at a fraction of signals?). If we accept that stopping at a red is an acceptable part of the safety mechanism, why can't we also accept that stopping at the absence of a green, or the absence of any signal, is? Tripcocks are present at all home signals on LUL lines. You meant to say: Tripcocks are present at all stop signals on LUL lines. Didn't you? Naturally. Does 'stop signal' mean 'signal capable of telling a train to stop', ie anything that can go red, as opposed to route indicators etc? If so, i hadn't realised that, i stand educated, that's a very good thing, and i'm surprised there wasn't something along those lines protecting the wrong-way move that was possible here, some sort of always-on tripcock alongside the board saying YOU ARE GOING THE WRONG WAY. tom -- Give the future a chance! |
#49
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#50
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In message . li, Tom
Anderson writes Tripcocks are present at all home signals on LUL lines. You meant to say: Tripcocks are present at all stop signals on LUL lines. Didn't you? Naturally. Does 'stop signal' mean 'signal capable of telling a train to stop', ie anything that can go red, as opposed to route indicators etc? If so, i hadn't realised that, i stand educated, that's a very good thing, and i'm surprised there wasn't something along those lines protecting the wrong-way move that was possible here, some sort of always-on tripcock alongside the board saying YOU ARE GOING THE WRONG WAY. Basically yes. Of course a route indicator will always have a stop signal with it (as in a "you can now go and you are going to go this way" signal). If a line is not intended for bi-directional running (as it isn't in the case under review) there is no need to provide signals for a route that isn't, in normal circumstances, able to be used. I say normal circumstances as there is always the possibility of doing a Wrong Direction Move, however in the case of a WDM there is paperwork involved and a whole safety procedure to follow so it isn't something that's done lightly. I've never done one in anger in 9 years. One additional item of protection that has been provided after some incidents in the deep and distant past is fixed red lights as a reminder at strategic places where an unusual move might possibly be made. I am aware of at least one at Kings Cross WB Picc at the tailwall end that has an associated train stop. The train stop automatically lowers when a train approaches from the correct direction to avoid the train being rear tripped. It then rises again as the train is fully berthed so that any attempt to change ends and drive the other way will result in the train being front tripped. I couldn't possibly comment on whether this move has been attempted in the past whistles innocently (No! not me ![]() -- Steve Fitzgerald has now left the building. You will find him in London's Docklands, E16, UK (please use the reply to address for email) |
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