Deleted
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Post by Deleted on Oct 18, 2007 13:25:22 GMT
I have read about wrong sticks and what can happen with them, but is the following a possible, however unlikely, scenario, and if so, what would happen?
Approaching a junction, the points are set for the diverging route, and the signal is clear but the junction indicator lights have all failed, making it seem like the train is signalled to go ahead. The driver of a wrong train then accepts what appears to be a right signal, and ends up in the wrong place.
Presumably, if this can happen, it cannot be down to the driver accepting the wrong stick as he couldn't see it was wrong.
If this already fairly unlikely scenario can't happen in the first place, how is it prevented?
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Post by tubeprune on Oct 18, 2007 13:29:55 GMT
At least two of the three lamps must be lit otherwise the signal will continue showing red.
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Post by chrish on Oct 18, 2007 13:33:47 GMT
At the risk of showing my complete ignorance of matters I should know about... I don't think the signal would clear if all the junction route lights have failed. The classic example is if you have a 3 way junction (left, right and straight), in which case the bottom white light is used in both paths... so if 2 of the others have failed on a route.. which way are you going? left or right? This example is straight out of T/op training, but I'll be honest and say I am not sure what we were told about it... just as I have said, I am not sure the signal would clear!
EDIT... good good... seems Tubeprune has already proved me right! My brain still works! ;D ;D ;D
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Post by railtechnician on Oct 18, 2007 13:47:46 GMT
At the risk of showing my complete ignorance of matters I should know about... I don't think the signal would clear if all the junction route lights have failed. The classic example is if you have a 3 way junction (left, right and straight), in which case the bottom white light is used in both paths... so if 2 of the others have failed on a route.. which way are you going? left or right? This example is straight out of T/op training, but I'll be honest and say I am not sure what we were told about it... just as I have said, I am not sure the signal would clear! EDIT... good good... seems Tubeprune has already proved me right! My brain still works! ;D ;D ;D The common light in your example is known as the pivot light. If another harbour light is blown with the pivot light that route will not clear whereas the other route will still have two working lights. The route clears when the current drawn by the route lamps is sufficiently high, this means that the bulbs do not necessarily have to be blown to cause the lights to fail or the signal to remain at danger although that is the most likely cause! Brian |
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Post by Deleted on Oct 18, 2007 14:01:49 GMT
I might have guessed that had been thought of... many thanks. Oh, and nice Tux, railtechnician.
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Post by Deleted on Oct 18, 2007 14:20:27 GMT
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Tom
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Post by Tom on Oct 18, 2007 14:55:21 GMT
You're sort of there.
3 filaments to pick the UECR, UECR picks the GR.
What you always need to be very careful of when there are two (or more) route indicators is that there aren't any funny return paths if a fuse blows. Quite a few sites have 20A (N)UE fuses after an incident a couple of years ago.
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Post by Deleted on Oct 18, 2007 18:07:32 GMT
btw UECR = Route Light Checking Relay
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