Running shunt signals when talking past a main signal

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Running shunt signals when talking past a main signal 09/02/2025 at 20:15 #160143
fbfree
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2 posts 		I have a general question, although I encountered it recently when running Swindon A&B. In that simulation, at Swindon, the overlap on the up route into Platform 1 had a track circuit fail. The routes into this platform have running shunt signals.

When talking a train past the main signal to get into the platform, is it correct to set the shunt route from the running shunt signal, so that it clears? If the driver ran past such a shunt signal set on, would he have to stop and report it?

I'll add a screenshot tonight if I get a chance.
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Running shunt signals when talking past a main signal 09/02/2025 at 20:59 #160144
Stephen Fulcher
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2101 posts 		Always clear a signal if you can, even a shunt aspect is still better than talking by as it will prove the route.

Rules wise, and others are better than I at this aspect of the railway, you should probably stop the driver at the main aspect and explain what you are doing before clearing the shunts.
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Running shunt signals when talking past a main signal 09/02/2025 at 23:03 #160145
TUT
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557 posts 		One of your questions was explicitly addressed in the December 2020 rule book updates.

The rules for drivers now state explicitly:

Quote:
4.6 Position-light signals not associated with a main aspect signal and semaphore shunting signals

If the signaller authorises you to pass a main aspect signal or semaphore stop signal at danger, this allows you to proceed as far as the next main aspect stop signal or semaphore stop signal ahead, ignoring the aspect displayed by any of these types of signals that are in the route:
•position-light signals not associated with a main aspect signal
•semaphore shunting signals.

However, if the signaller tells you that the train is only authorised to proceed up to a specified position-light or semaphore shunting signal, you must:
•only proceed as far as that signal
•stop at it, whatever aspect is displayed.
In other words, if you authorise a driver to pass a main aspect signal at danger they will ignore running shunt signals unless you tell them otherwise.

On the signaller's side of the coin the rules were altered to require:

Quote:
3.1 Instructions from the signaller

You must tell the driver if the train is only authorised to proceed as far as a specified position-light signal not associated with a main aspect signal or a semaphore shunting signal before reaching the next main aspect stop signal or semaphore stop signal ahead.
The rules were altered in response to incidents where trains had proceeded further than intended (presumably past position-light signals that the signaller wanted the train to stop at but hadn't made this clear).

Setting that aside, in general when you pass a signal at danger you must call the route on a panel or workstation if you can. One of the exceptions to this is if there is a track circuit failure in the route concerned, as you risk route locking yourself. In this situation, clearing S231 position-light signal wouldn't route lock you and would prove the route so I would certainly consider it quite a sensible precaution to clear it, though if you didn't the driver wouldn't stop at it as of December 2020 unless you told him to (in which case he should stop at it even if you have pulled it off).

If you were working mechanical and you had mechanical point detection then you would really, really need to clear any ground discs in the route as they will prove the points are correctly set. If you can't clear the ground disc, it's a fair bet that the reason is you haven't got the detection, so you really don't want to talk past the main signal then, cause your train might end up on the floor. The rules would require you to clip and scotch the points before S5-ing in that case, unless there is an FPL and you have checked that it is properly engaged, or had this confirmed by somebody else.

That however is real life. If memory serves SimSig occasionally throws a bit of a wobbly when you try and pass a signal at danger with a running shunt in the route. That might be a bug that has long since been fixed, but I think SimSig will probably play a bit nicer if you do just clear the signal.
Last edited: 09/02/2025 at 23:05 by TUT
Reason: None given
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Running shunt signals when talking past a main signal Yesterday at 16:29 #160155
clive
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2808 posts 		TUT in post 160145 said:

If you were working mechanical and you had mechanical point detection then you would really, really need to clear any ground discs in the route as they will prove the points are correctly set. If you can't clear the ground disc, it's a fair bet that the reason is you haven't got the detection, so you really don't want to talk past the main signal then, cause your train might end up on the floor. The rules would require you to clip and scotch the points before S5-ing in that case, unless there is an FPL and you have checked that it is properly engaged, or had this confirmed by somebody else.
There was a nasty crash at Lichfield in mechanical days (1946-01-01). The FPL was jammed with the points reversed but the signaller was able to normalize the FPL lever and then the facing points lever, then pull the FPL lever over again. That meant the signal requiring points normal was able to be cleared and a fish train ran into the back of a passenger train, killing 20 people. The points lever was bent under stress and so the points hadn't moved even though the lever did.

Experiments showed that the signal couldn't be cleared because of a detector. Nevertheless several witnesses said they saw the signal light green (it was a clear night) and two distant signals were also clear (though the detectors wouldn't prevent that).
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