Setting back

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PhilipWillis
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Joined: Sat Jan 30, 2021 6:51 pm

Setting back

Post by PhilipWillis » Thu Feb 04, 2021 9:21 pm

Did the LNWR ever use small stand-alone semaphore signals for setting back?

I am thinking of the case where a loco might move forward beyond a Starter and fouling distance (but with an 'on' Advanced Starter still ahead) and later need to reverse on the same line to behind the Starter, essentially to where it started. The loco would need to be held beyond the fouling distance before being permitted to reverse, suggesting the need for a backing signal but I have yet to find any evidence.

Any information gratefully received.

Philip

Signalman70
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Joined: Wed Mar 06, 2019 2:23 pm

Re: Setting back

Post by Signalman70 » Wed Feb 10, 2021 5:21 pm

I think 'set back' discs, let alone signals, were very much the exception in L&NWR signalling.

Despite 'Working In Wrong Direction' being authorised between all of the Chester boxes no discs/signals were provided for these moves, reliance being placed on Hand Signals, even from the 'Big' boxes.

Dave

Mike Williams
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Re: Setting back

Post by Mike Williams » Wed Feb 17, 2021 9:36 am

I know little about signalling but maybe this is sort-of similar?

At Aylesbury (terminus station) there was no engine release so the train was backed out of the platform for running round. A standard ground signal was provided for the driver in order to do that, as from his position he couldn't see anything else.

Mike

Signalman70
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Re: Setting back

Post by Signalman70 » Mon Feb 22, 2021 12:51 pm

The ground disc mentioned by Mike Williams at Aylesbury L&NW would presumably be associated with the starting signal from the single passenger platform and govern route(s) to sidings.

Dave

Mike Williams
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Re: Setting back

Post by Mike Williams » Mon Feb 22, 2021 3:25 pm

Yes Dave, that is correct. The ground signal repeated the starter which was a standard semaphore except for the arm which was short.

Mike

Signalman70
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Re: Setting back

Post by Signalman70 » Tue Feb 23, 2021 1:43 pm

It wouldn't 'repeat' the starter - it would be cleared for the siding routes.

I did find a very old photo showing the main arm full size with a short subsidiary arm beneath.

Mike Williams
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Re: Setting back

Post by Mike Williams » Fri Feb 26, 2021 9:29 am

You are quite right - apologies. My Dad always referred to it as the starter, but it was of course co-acting with the shorter arm. I still have that short signal arm at home!

Sorry to go off at a tangent, but at Aylesbury there was just one running line and when setting back from the platform you could only to straight down that or left into the goods reception road, which was rarely used for passenger trains. The points into the passenger run round loop were trailing when you leave the platform. I always assumed the co-acting signals gave permission to run as far as the next home signal to stop and run round. But isn't that what the starting signal did too? In short, what was the difference between the two in operation?

Mike

Mike Williams
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Re: Setting back

Post by Mike Williams » Fri Feb 26, 2021 9:36 am

This is a model but shows the platform, the starter signal and second arm. The crossing with its own home signal is in the distance.

Mike
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Aylesbury overhead view.jpg
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Signalman70
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Re: Setting back

Post by Signalman70 » Fri Feb 26, 2021 12:29 pm

Mike, we need to clarify our terminology,

Co-acting = signals which work together for sighting purposes e.g. an arm on a tall post for sighting over a physical obstruction, co-acting with another arm lower down for closer viewing. (still sometimes used with colour light signal heads such as at Birmingham New Street near the tunnels, a ground-mounted signal head co-acting with an elevated one).

Subsidiary Signal - distinguished from the 'Main' arm by being smaller, could be used as a 'Shunt Ahead', 'Call On' (towards an occupied line) or 'Warning' (that the line was only clear to the next signal). Subsidiary signals give permission to pass the 'Main Arm', mounted above, at Danger.

I think that's enough for now, as it can get complicated with various arrangements used in different places/time periods. For example, Rule Book clauses covered situations where 'Sub' signals were not provided.

Please feel free to ask any further questions.

Regards, Dave

PhilipWillis
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Joined: Sat Jan 30, 2021 6:51 pm

Re: Setting back

Post by PhilipWillis » Wed Mar 03, 2021 11:38 am

Thank you everyone.

Other material I have found confirms that shorter semaphores were occasionally used, for the purposes described in this thread. It looks like they could also be deployed to control reversing too. By the sound of it, this may be rare!

Thanks again.

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