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Do I need a shunt ahead signal here?

Posted: Wed Aug 12, 2020 12:17 pm
by Randy
Hi,

Era being modelled: BR late crest. Region, somewhere in the midlands, originally a Midland railway turned LMS, turned BR LMR, but fictitious.

Annotated photos for reference below. I have a small goods yard which is to be served by pick up / drop off goods trains, where trains will need
to shunt, propelling into the yard. I am placing an advanced starter signal at the end of the layout where I have drawn it on. My question is, for a prototypical layout, do I need a shunt ahead subsiduary arm on this post? This would be needed in case the train being shunted is too long to fit between the points and signal.
In terms of the actual model, the largest train the fiddleyard can hold is not long enough to need a shunt ahead, so the signal wont actually be used for model workings, I'm asking from a prototypical standpoint. The goods yard is also small, so in my mind this may mean it is not served by any particularly large goods trains, however I have no knowledge of the workings of any real place like this in this time, so that assumption may be wrong.

The scale distance between points and advances starter signal is just over 100m.

Fundamentally, I'd like to know if it would make sense with or without a shunt ahead, and if either one would be unprototypical. (It will save a fair bit of effort if I don't need to make the subsiduary arm.)

Thanks for your help!

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Re: Do I need a shunt ahead signal here?

Posted: Thu Aug 13, 2020 5:23 am
by LC&DR
Shunt ahead signals were provided to save time where regular shunting moves were being made into the section ahead but were not always necessary where it wasn't a regular move but was needed occasionally.

Regulation 31 required the signalman to obtain the assent of the next signalman by sending "Shunting into forward section" (bell code 3 pause 3 pause 2) and when this was acknowledged he had to verbally instruct the driver of what he was allowed to do. The signalman was then allowed to clear his section signal for the shunt to take place.

If a "Shunt ahead" signal was provided however the signalman did not need to verbally instruct the driver but was allowed to clear the Shunt ahead signal instead.

When the shunt was completed and the train returned inside the section signal the signalman should then send "Shunt withdrawn" (bell code 8 beats).

Things got a little more complicated where the section signal was locked by the block controls, but otherwise the principles were the same.

So you may decide not to put a "Shunt ahead" signal under your section signal but leave it to your signalman to verbally instruct your driver each and every time.

Re: Do I need a shunt ahead signal here?

Posted: Thu Aug 13, 2020 10:40 am
by Randy
Thanks LC&DR.

Very useful and interesting information. Now that I’m justified in not having a shunt ahead, I won’t bother with it.
I did actually have one built up and almost ready, but part of it broke, meaning almost all of it has to be repainted and rebuilt. I don’t think I can face doing it all again with both arms!