Signalling query - shunt arms and advanced starters?

[Nick C]

I'm starting a new layout based loosely on the Horsham-Guildford line in the 1950s - so ex-LBSCR with some SR modernisation. I'd like it to be correctly signalled to SR practice, as much as possible (distants will be off-stage)

 

I've got the track plan sorted - basically Cranleigh with slight changes to the goods yard for reasons of space, but I'm wondering about suitable signalling. The box diagram I've got for Cranleigh shows shunt arms on all three starters (a dummy on the Up starter, and ringed arms on the Down and Down-from-up-platform), and no advanced starters - would that have meant that a staff would have to be withdrawn for every shunt move?

 

There's also a shunt arm shown on the post of the Down home, followed by a running shunt at the loop points - why would they have both? At the other end there's only the home and running shunt.

 

The below Sigscribe extract is what I had drawn up before looking at the Cranleigh diagram - with the assumption that 11 is a yellow miniature arm, and the starred signal (8 and 9) is a semaphore with a shunt arm or post-mounted dummy to allow access to the yard.

 

 

Differences with Cranleigh (can't post the Pryer diagram here for copyright reasons) are - no advanced starters (4, 15); shunt dummies/arms on the signals I've numbered 1, 16 & 3, and at the up end of the down loop (down being left-to-right); I've missed off the distants as they're off-stage; yard layout is different and I've missed off a trap at the up end of the down loop.

 

Bearing in mind that I'm not doing an exact copy, should I stick with what I've got, or go closer to the prototype?

[The Stationmaster]

What date does George Pryer give for his diagram - it sounds very LB&SCR s with the ringed arms?

[Nick C]

There's no date on the diagram unfortunately!

 

The Middleton press book shows SR upper quadrant 'S' arms on the platform starter posts by 1951. 

[The Stationmaster]

Right some delving on the 'net has been very useful.  Your Signal 3 had a Shunt Ahead subsidiary arm in its railbuilt form,  the one opposite (8/9) didn't have a subsidiary arm so probably had a disc somewhere near to read into the sidings, it looks to have been at ground level adjacent to the post but the picture isn't very clear ).  16 doesn't appear to have a subsidiary arm in later photos but might well have had a Brighton ringed subsidiary arm at some time, it definitely appears to have had no subsidiary in rail built form and it wasn't there in late pictures of the Brighton signal.

 

I can't find any pictures including the Home Signals but presumably there were some although you haven't shown them.  The position of trains suggests there might have been a splitting Home at the left hand end in your drawing as the line nearest the signal box appears to have been used in either direction?

 

The existence of a shunt Ahead Arm below 3 confirms there was no Advanced Starting Signal in that direction and I doubt the line was busy enough to justify such a luxury in any case.  Trains simply shunted out onto the single line section as needed with or without a token (or whatever it was - probably a tablet) depending on teh wording of the SR Regulations (which I haven't checked) but in various circumstances it wasn't necessary to withdraw a token etc in order to make a shunt onto the single line at a crossing station.

[Nick C]

6 minutes ago, The Stationmaster said:

Right some delving on the 'net has been very useful.  Your Signal 3 had a Shunt Ahead subsidiary arm in its railbuilt form,  the one opposite (8/9) didn't have a subsidiary arm so probably had a disc somewhere near to read into the sidings, it looks to have been at ground level adjacent to the post but the picture isn't very clear ).  16 doesn't appear to have a subsidiary arm in later photos but might well have had a Brighton ringed subsidiary arm at some time, it definitely appears to have had no subsidiary in rail built form and it wasn't there in late pictures of the Brighton signal.

 

I can't find any pictures including the Home Signals but presumably there were some although you haven't shown them.  The position of trains suggests there might have been a splitting Home at the left hand end in your drawing as the line nearest the signal box appears to have been used in either direction?

 

The existence of a shunt Ahead Arm below 3 confirms there was no Advanced Starting Signal in that direction and I doubt the line was busy enough to justify such a luxury in any case.  Trains simply shunted out onto the single line section as needed with or without a token (or whatever it was - probably a tablet) depending on teh wording of the SR Regulations (which I haven't checked) but in various circumstances it wasn't necessary to withdraw a token etc in order to make a shunt onto the single line at a crossing station.

 

Thanks - I've been hunting the net as well and managed to find a few photos.

 

The down home (1 in my diagram) is shown as a single stop arm with a ringed arm underneath. I suspect that the Up platform (the one nearest the box) was only signalled for departues in both directions, as several trains terminated from the Guildford direction. That ringed arm was one of the things confusing me, as a loco running round would surely use the running shunt at the loop points? Unless that arm was to signal down goods trains into the up platform?

 

The bottom photo on This page shows a shunt arm on my 16 in 65, as does a shot on disused stations. Upper quadrant but still on the wooden post.

 

This photo just about shows the signal I've numbered 8/9, as you suggest it's a single arm with a dummy at it's foot.

 

This one shows the down home - hard to see clearly, but definitely one full size arm and one short one on the same post.

[RailWest]

SR records for the 1930s state Electric Train Staff working. I doubt the L&BSCR had any tablet sections?

[Nick C]

So, following the above advice and the additional photos I've found, I've re-done it closer to the original:

 

 

I've added the distants (unworked, they are 2 and 17 on the Pryer diagram, but I wanted to keep it under 18 levers...)

 

#1 is noted as selected, presumably based on the position of points 10. The original shows the FPL on 12A, and both arms on the signal I've numbered 6,2 as being operated by lever 8. Presumably a LBSCR peculiarity? Can you have the FPL and signal done off the same lever? As the stationmaster suggests above it's probably a pre-grouping diagram...

 

 

[RailWest]

>>>Can you have the FPL and signal done off the same lever....

 

The L&SWR certainly had a few examples, tho' I've not encountered one with the extra feature of selected signals. Goodness knows how the detection worked!

Edited June 15, 2019 by RailWest

[bécasse]

12 hours ago, Nick C said:

The original shows the FPL on 12A, and both arms on the signal I've numbered 6,2 as being operated by lever 8. Presumably a LBSCR peculiarity? Can you have the FPL and signal done off the same lever? 

 

 

The LBSCR normally fitted economic FPLs where the FPL and the point were worked by the same lever. I haven't seen a diagram for Cranleigh but certainly Baynards on the same line had economics.

[Martin Shaw]

Quote

The LBSCR normally fitted economic FPLs where the FPL and the point were worked by the same lever.

Bit of a sweeping statement, which really isn't correct. The LBSC certainly used them sparingly where they had usually run out of spare levers, but they weren't run of the mill as the Midland used them. I have copies of the Wagstaff drawings which are dated 1920 and at that time Cranleigh had an EFPL, lever 9 which had by the time of Pryer become the FPL , the switches became 10 which was henceforth a crossover. Baynards didn't have any EFPL's but a slightly odd 2 lever GF which worked the loop points and FPL furthest from the box. The points were bolted normal and reverse by two of the box levers which released the relevant signals. It's interesting to note that the section from Baynards to Rudgwick was worked by train staff and ticket with Harpers instrument, disitinctly different from the Webb and Thompson ETS one might associate with LBSC single lines. Given that Pryer dates the Baynards drawing as 1935 it's reasonable to assume that the Cranleigh drawing is similar. It was I think 1925 when the limit for mechanically worked points was extended to 350 yards.

 

The Brighton were quite fond of floating wheel detectors where selected functions were required from the lay of points usually, but I see no reason why an FPL should be inherently different, so two signals and an FPL from one lever is quite possible if a bit of a maintenance liability.

Regards

Martin

[bécasse]

Apologies for my error in respect of EFPLs at Baynards. I had looked at its signalling diagram for another purpose only a couple of months ago and somehow come away with the mistaken impression that EFPLs were fitted there. I usually recheck such things before posting but stupidly failed to do so on this occasion!

Thanks to Martin for pointing out the error of my ways!

I still haven't sorted out in my own mind as to whether the Brighton only used EFPLs when it was short of levers or if there was sometimes some other reason. I have come across more photos which appear to show them than I would have expected to if the former was the case, but, of course, it could be that the presence of an unusual feature was one of the reasons that the photo was taken - it can be a great mistake to assume that old photos are representative of the everyday life and times of a railway.

[Nick C]

Another question on this - I'm in the middle of laying the track, and realised that I need to work out some of the signal positions at this stage to avoid them falling directly over board joints!

 

In particular, the running shunt 8 and the down home 3/7 - looking at the photo I lined above and the 6inch map on the NLS site, it looks like the shunt is at the toe of the points, and the home about 200ft in advance. There's a photo on disused-stations circa 1923 (here) that clearly shows a locking bar at the toe of the point, but one here that doesn't - clearly later as the starter has an upper-quadrant arm. Therefore presumably the shunt would have to be far enough away to allow for the length of the locking bar? Does the absence of a bar in the later photo suggest that it was track-circuited, and if so, would the signal have been moved closer?

 

Similarly the P1 down starter 6/2 - it looks from photos that this was pretty much at the toe of points 12A - would it actually be a locking-bar-length away? Would it be likely to be track-circuited by the 1950s?

[Martin Shaw]

Nick

If you compare your two linked photos, the earlier one shows a vaguely triangular device to the left of the points, this is a hook selector used to determine which signal of two worked from one lever would clear as determined by the lay of the points. In the later pic this has disappeared and replaced by a weighted detector, used to ensure the detector slide fully clears the notch in the stretcher. I have found on David Hey's site a picture taken in the opposite direction for the platforms and the running shunt has been removed, and with that gone the locking bar is pretty much redundant, so likely BR took it away. Track circuits on a secondary byway are exceptionally unlikely, to a point I can almost say definitely not. Hope this helps.

Regards

Martin

Edited July 31, 2019 by Martin Shaw

[Nick C]

Thanks Martin - so with neither a locking bar nor TC, what would have stopped an errant signalman putting the FPL back and changing the points under a train? Especially if there wasn't a running shunt? Would there have been treadles and a backlock on the home signal? Or is that a more recent thing that again wouldn't have been there on a rural backwater?

[Martin Shaw]

Nick

In answer to your question, absolutely nothing, although to be wholly fair to signalmen throughout history I can only think of a small handful of incidents where signalmen have bent or broken rules that resulted in loss of life, and in truth really only one where the signalman possibly had malice aforethought. There was and possibly still is a regulation such that signals cleared for routes with points in them should not be returned to danger until the train has cleared the points, so holding the locking. Treadles and backlocks, not really.

Martin

[The Stationmaster]

15 hours ago, Martin Shaw said:

Nick

In answer to your question, absolutely nothing, although to be wholly fair to signalmen throughout history I can only think of a small handful of incidents where signalmen have bent or broken rules that resulted in loss of life, and in truth really only one where the signalman possibly had malice aforethought. There was and possibly still is a regulation such that signals cleared for routes with points in them should not be returned to danger until the train has cleared the points, so holding the locking. Treadles and backlocks, not really.

Martin

Most versions of the Block Regulations down the years required the route to be set, and the points locked by the FPL, right  through to the Clearing Point before 'Line Clear' could be given.  The Rules required that stop signals must not be returned to danger following the passage of a  train until it had passed in advance of all facing points to which that signal applied.  That still applies in the General Signalling Regulations although the wording has been reduced to LCD level with no use of unambiguous terms such as 'in advance of' (it now says 'clear of' and is not worded very positively in that it says 'must ... after'  rather than 'must not  ... until').

 

A Rule not infrequently observed in the breach but as you have said in modern times there have only been a handful of incidents where loss of life has resulted.

[31A]

17 hours ago, The Stationmaster said:

 

A Rule not infrequently observed in the breach but as you have said in modern times there have only been a handful of incidents where loss of life has resulted.

 

http://www.railwaysarchive.co.uk/eventsummary.php?eventID=492

[Nick C]

2 hours ago, 31A said:

 

http://www.railwaysarchive.co.uk/eventsummary.php?eventID=492

That's pretty scary reading!

[DCB]

Just idly wondering how on earth you shunt/they shunted,  the sidings. Well it is 5 am and I have tooth ache.

[Dunsignalling]

1 hour ago, DavidCBroad said:

Just idly wondering how on earth you shunt/they shunted,  the sidings. Well it is 5 am and I have tooth ache.

From the layout, I'd suspect the yard was only served by goods trains travelling in one direction (left to right on the diagram) with anything arriving from the other end being tripped to the next location from which it could be sent back.

 

John

[DCB]

1 hour ago, Dunsignalling said:

From the layout, I'd suspect the yard was only served by goods trains travelling in one direction (left to right on the diagram) with anything arriving from the other end being tripped to the next location from which it could be sent back.

 

John

That's what I wondered but I would have expected the route from left to the lower platform to be signalled, otherwise the right to left train could shunt the yard after the loco runs round, it all looks a bit awkward.

[Dunsignalling]

16 minutes ago, DavidCBroad said:

That's what I wondered but I would have expected the route from left to the lower platform to be signalled, otherwise the right to left train could shunt the yard after the loco runs round, it all looks a bit awkward.

Agreed. As drawn, the L-to-R goods would either have to reverse into the loop or be stopped short and brought in on a shunt signal. Local regs would presumably specify anything unusual being permitted/necessary.

 

Another possibility might be that goods trains came from the RH end and didn't go any further.

 

The presence of a starter going right on the lower platform but no corresponding home suggests it could also be used as a turnback road for terminating passenger trains but the absence of a home signal indicates its not fully bi-directional.

 

All in all, rather odd, but, unfortunately, I'm not familiar with the prototype location so that's about as far as I can surmise.

 

John

Edited August 3, 2019 by Dunsignalling

[Nick C]

There were indeed terminating passenger trains from the right (Guildford), as I've moved the location, I was going to drop that starter as my location would be unlikely to have terminating trains. I've not got a WTT for the line, but I'd presume that goods trains would run the full length. The original also had a gasworks at the end of the headshunt that would presumably have been shunted from the opposite direction.

 

I've come across another question - as drawn, I've got the lower of the two platform roads as the diverging route on the right hand crossover, mainly because it fits better that way in the space I've got. However, that is the platform with both the box and the station building, so ought I change it so that is the straight route, or would it not matter (especially as all arriving trains would have to slow right down for the token exchange anyway)? I've already laid that crossover, so I'm hoping it will be ok!

[Nick C]

So to revisit this topic - I've just come across a copy of the Cranleigh box diagram from the '60s, and found a feature that I've never seen before:

That is - lever 9 works the loop points, lever 10 works the FPL on 9, and the trap points. There's a similar arrangement shown at the other end, but using the yard access points rather than a trap.

 

Was it a common arrangement to have a lever working an FPL and a separate set of points, rather than one lever working both ends of the crossover and another doing the FPL?

[RailWest]

I've never seen an arrangement like that before, so would be interested to know how common it might have been.

 

Can you post a copy of, or link to, the SB diagram please?

 

Edited September 23, 2020 by RailWest