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Latest Layout: Signal Advice Needed, Please


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I am in the process of planning a new layout and would be grateful if anyone could advise on the positioning of signals. The layout is set in the 1980s Western Region (Semaphore signals) and consists of a cross country double track passing through a station including a small engineers siding and is 9ft long.

 

I have limited knowledge of signals and do not have any railway experience although I have done some background reading and had a go at positioning signals (see attached image).

  • On the top line (left to right) I have shown a HOME signal protecting the crossover and a STARTING signal at the end of the platform.
  • On the bottom line (right to left) I have shown a STARTING signal at the end of the platform
  • In total I have shown six shunting signals indicated by small grey circles.
  • I have not included any DISTANT signals or ADVANCED STARTING signals as due to the size of the layout these would be off scene.

 

I would be grateful for any comments on these arrangements but in particular,

1. Are the home and starting signals correctly positioned on the layout and on the correct side of the track?

2. Is my assumption about DISTANT and ADVANCED STARTING signals correct?

3. Really not sure about the shunting signals - are they all necessary and on what side of the track should they be positioned?

4. I have done some research about trap points and have come to the conclusion that due to the arrangement of this yard a trap point would not be necessary - is this correct?

5. I have assumed that the point in the yard would be operated manually and the yard would not need any signals - is this correct?

6. What is the likelihood that this type of station would have had a signal box in the 1980s. If so, where would be the most likely position?

 

Any help with any of these points would be most helpful.

 

Many thanks in advance of any support. 

Track Plan Signals.jpg

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Is there a terminating passenger service using the bay to reverse?

If yes, then you need a trap point to protect the bay from the sidings.

If no, then I doubt there would be a facing crossover for access to the sidings via a headshunt, more likely to be trailing access with the sidings facing the other way.

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Peter,

 

I'm no expert, particularly with semaphore signalling, but I'd answer your questions as follows:

 

1. The positions shown seem reasonable.  The signals would be placed to the left of the running line that they apply to, which is what you seem to have shown.  In the case of the starter signal in the top right of your drawing, the crossover would have to be locked to allow a train to run into the platform (because it's in the overlap (the distance beyond a signal that needs to be clear to accept a train up to the signal)).  This crossover couldn't be used if you have a train sitting in the left to right platform. 

 

I think the Home signal that you have shown top left would actually be offstage to the left.  I'd expect there to be enough space between the home signal and the crossover to allow a locomotive to use the crossover within 'station limits' whilst a train may be held at the home signal.  However, I'm not going to say that it's wrong where you have it.   If you intend passenger trains operating into the bay, then this signal is likely to be a splitting junction type with the larger post for the mainline and the smaller post for access to the bay.  If however, the bay is only to access the sidings, the trains would be brought to a stand at the home signal and then your shunt signal would control access through the crossover to the bay.

 

2.  Your assumption about distant and advance starter signals is correct.

 

3.  Again your shunt signals would normally be placed to the left of the line that they relate to.  I'm not sure whether you need all of these because I'm not sure what shunt movements you think you are likely to make.  Try to think about what movement you think each one is controlling and only include shunt signals for the movements you anticipate making.

 

4.  If the bay is not used by passenger trains, then a trap point would not be required for the layout shown.  However, as per the response above, if you will operate passenger trains into the bay platform, then the sidings would need to be trapped.  The purpose of trap points is to stop errant rolling stock fouling passenger lines.  As per the response above, facing crossovers on the mainline were generally avoided, so the reason for including one is most likely that you'd have a passenger train terminating in the bay platform.

 

5.  The point in the yard could be operated manually.  Whether the point from the bay to the sidings is manually operated is likely to depend on whether or not the bay platform is used by passenger trains or just for access to the sidings.  In the later case, it would probably be hand worked, but if the bay is used by passenger trains, it would probably be controlled by the box.  There wouldn't be a need for signals in the yard.  Hand signals by the shunter would suffice.

 

6.  I think it's plausible that you could have a signal box if you want one - there are or were still some around in the 21st century.  It is most likely to be situated such that you minimise the distance between the levers in the box and the points and signals that the box controls.  I'd probably go with somewhere near your baseboard join - ie halfway between your crossovers near the letter C on your left to right line. 

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  • RMweb Gold

Hi Peter,

 

I'm willing to take a punt and see if the experts agree. (Dangerous, I know!)

 

The station would almost certainly have had a trailing crossover on the left in it's earlier days and it feels like a location that would not have been a high priority for rationalisation so my feeling is it would still be trailing in the 80s.

 

If we call the top track "Up" and the bottom track "Down", and assuming that the Bay is for passenger use, then:

  • I think you need a Down Home signal just above the "k" of "Car park".
  • There is a ground disc to the right of the Down Starting whose purpose is unclear (to me, anyway!). I would remove it.
  • Trap as per Dungrange point 4.
  • A ground disc at the toe of the trap point, indicating that the route from yard to bay is safe.
  • I think you need a ground disc to signal the setting back movement from the Down Main into the bay. Positioned above the toe of the bay points, between Up and Down ("in the 6ft"). If the left hand crossover becomes trailing that disc might be combined with the disc for the crossover setback move as a double disc.
  • The Bay needs its own starting signal, at the toe of the points from bay to yard.
  • The ground disc shown to the left of the Down Starting should be moved below the toe of the points leading from bay to yard, alongside the Bay Starting.
  • Signal box would probably be on the Up side, anywhere between the Up Home and the platform. 

 

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  • RMweb Gold

We really need an answer as to whether that is a bay for terminating trains or just a siding.

 

If it is just a siding, then that facing crossover needs to go and be replaced by a trailing crossover.

 

By the 1980s, most of the secondary WR routes had been singled. Might be an idea to make one end single track to add operational interest.

 

Signals are generally set on the left. But where visibility is compromised (curves, bridges, station canopies), they could be on the right. Especially on the GWR which had right-hand-drive locomotives.

 

A signal box is mandatory with mechanical (semaphore) signals. It would be placed, usually, wherever would give the simplest operation of the pointwork but also with consideration of unobstructed lines of sight.

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  • RMweb Gold

Some comments as others -

1. That facing crossover is very wrong unless the layout has been changed to simplify thing for a terminating/turn round train which would run to the bay line.  But if that is the case additional additional signals would obviously be needed.

2. Joseph Pestell is spot on - by the 1980s most WR secondary routes had been singled although some of the more important and busier ones had not.  If you have double liine it will have to reflect the traffic situation of one of the remaining doubled sections if you want it to look realistic.

3 As far as your running signals (the semaphores are concerned those protecting trailing crossovers need to be a little bit in rear of the trailing connection in the opposite line. which means -

the one on the right needs to be at the foot of the platform ramp

you need an additional one on the opposite line more or less opposite the ground disc for the other line.

the one at the end of the lower platform needs to be moved back towards the platform end

4. As the GWR always 'locked two back' with signals protecting trailing points the position of a signal protecting a trailing point is basically a matter of correct siting for clearance from the fouling point of the crossover and nothing to do with any locking restriction.  The trailing crossover at the right on your sketch would lock at danger both signals applying to that line when standing in reverse.

5. The ground signals are a bit odd partially as a result of that facing crossover but -

the signal reading from the 'bay line' needs to be at the toe of the points and would be a yellow arm disc by the 1980s.

you definitely need an additional disc at the toe of the points leading back into the 'bay line'

I can't see any need at all for a ground disc at the signal at the left hand end of the platform - it serves no real purpose from what I can see.

 

6.  Now to deal with that facing crossover.  Either what looks like a bay line is a bay line for passenger trains or it isn't.  If it is a passenger bay by the 1980s it's reasonable to assume that a facing crossover might have been provided to deal with a DMU going into the bay to reverse and leave from there.  In which case the Home Signal on the left would need to be a splitting signal with one arm reading to the through line and the other reading to the bay.  You would also need a running signal reading from the bay plus - as already mentioned a trap point in the sidings to protect the bay from anything coming out of those sidings.

 

7. However if we wind the clock back a bit to the days when there was freight traffic to the station the facing crossover would have been trailing.  The reason for that is only trains running from left to right could easily shunt the sidings but if a train running from right to left needed to shunt them the engine, plus wagons for the sidings, would have to run round the rest of the train and you need two trailing crossovers to do that.   Equally that arrangement could be used to deal with a terminating passenger train which arrives from the left, the engine then runs round and subsequently shunts its train to the bay from which it could start back whence it had come (with a suitable signal reading from the bay and a trap point in the sidings as already described).

 

By the 18980s of course any freight traffic to from the station would be non-existent unless it was part of a very specialised flow.   For example it could be bitumen traffic in tank cars (which was the only traffic at two locations in my area in the 1970s) or possibly some very occasional specialised traffic - we had agricultural machines, occasional grain, and occasional military stores at another station.  But I did at that time have one station with a yard handling freight but it was really no more than some agricultural traffic (which was very seasonal).  General freight traffic had long been moved to what were known as concentration depots -something which happened in the 1960s.  By the 1980s any surviving sidings like thoat would most likely have been nabbed by teh civil engineers for stabling and servicing on-track machines such as tampersy

 

8. If you alter the left hand crossover to a trailing crossover the Home Signal on the upper line would be sited (placed) in the same way as the signals protecting the trailing crossover at the other end of the station i.e just n rear of the point toe on the opposite line.  On the Western signals protecting points were not normally set back any further than that from what they protected.  I can't actually understand the second paragraph of Item 1 in 'Dungrange's post because with a facing crossover you couldn't in any case get an engine onto the upper line with a train standing at the Home Signal, there'd be no room for it apart from anything else.  If it was a trailing crossover you could move an engine onto that line after a train has been brought to a stand at the Home Signal but it's a very unlikely move in everyday working because of the delay it would cause to the train standing at the Home Signal.

 

Apart from the facing crossover and a couple of errors with ground signals I think you've done a pretty good job for yourself before coming to seek advice.  There would of course have to be a signal box and it would be as near as possible to the main concentration of pointwork so ideally opposite the trailing point towards the 'bay line' but on the further side of the main lines.    You'd then come to the interesting area of Western signal nomenclature which would make the signal at the platform end by the 'bay line points' the Inner Home Signal while the signal off scene to the left would be the Starting Signal - the Western named stop signal in accordance with their physical position relative to the signal box and not according to what some might regard as their obvious operational function.

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Many thanks for all the time taken to write the detailed replies to my questions, they are very much appreciated and have given me lots to consider. They have also made me consider a number of new options and clarified the finer detail of signal placement. I have included some further points of clarification which help any further discussion,

 

1. The original design was for the yard to be a little used, slightly overgrown engineers yard similar to that described by 'The Stationmaster' (point 7).

 

2. The bay platform would probably have been used for passenger traffic in the past but was now disused and slightly overgrown and acting as a heads hunt for the engineers yard so the absence of a trap point could be justified.

 

3. I had a feeling that the facing crossover was non standard but included it to give easier access to the yard when running in on the top line (left to right) but as the bay platform is not used for passenger traffic this would be harder to justify. If the facing crossover was changed to a trailing crossover access to the yard from the top line (left to right) would involve a engineers train being reversed through the trailing crossover before being able to gain access to the yard. Would this type of move be common place?

 

Thanks again for your careful consideration. Over the next few days I will try and redraft the plans and signal placement based on the advice provided so far.

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  • RMweb Gold

I think that you have taken on board Stationmaster's advice and understood it. Based on what you have written:

1) An overgrown engineers' siding is very much in tune with the 1980s period and will be interesting to model;

2a) Trains would not have run into the bay in earlier times, so the facing crossover needs to be substituted by a trailing crossover.

2b) I can't see anyone bothering to take out the trap point between the siding and the bay, so you probably should model it.

3) The real railway always preferred shunting to facing pointwork and that's good for us as it makes layout operation so much more interesting.

 

This thread has got me thinking about something similar but in 0, for which I have some bits and pieces in store. 

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20 hours ago, Titanius Anglesmith said:

 

Mike, would you mind explaining what this means please? I’ve never come across the term before. Thanks

 

Mike will manage this better than me, but I will try.

 

Placement of signals on the GW was very different from the other UK railways. They preferred to have many more signal posts putting a signal to protect each piece of pointwork and therefore, as Mike mentioned, each signal very close to that pointwork. So the successive signals are placed far closer together. The example that I find easiest is the east end of Frome station on the Up lines. There, there was a starter for the Up Main and a starter from the bay. Only 50 yards further on, a bracket signal, one for the Up Main, one for the branch. Any other railway would have had four signal heads on a bracket (or gantry) at the platform end.

 

On other railways, where the signals are placed further apart, it is sufficient to arrange the interlocking so that each signal is interlocked with just the one immediately to the rear. But with signals much closer together (often as little as 50 yards in a station situation), you need the interlocking to work on the next signal back as well to give an adequate braking distance.

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>>>On other railways, where the signals are placed further apart, it is sufficient to arrange the interlocking so that each signal is interlocked with just the one immediately to the rear....

 

I would have to disagree, certainly to the extent that many L&SWR/SR location also locked 'two back'. To some extent it may depend upon how far in rear of the point the nearer signal was- if it was quite some way back, then there might have been considered sufficient overlap not to need to the lock the point with the next signal further in rear. But as a general principle IMHO I would always assume locking two back :-)

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3 hours ago, Joseph_Pestell said:

 

Mike will manage this better than me, but I will try.

 

Placement of signals on the GW was very different from the other UK railways. They preferred to have many more signal posts putting a signal to protect each piece of pointwork and therefore, as Mike mentioned, each signal very close to that pointwork. So the successive signals are placed far closer together. The example that I find easiest is the east end of Frome station on the Up lines. There, there was a starter for the Up Main and a starter from the bay. Only 50 yards further on, a bracket signal, one for the Up Main, one for the branch. Any other railway would have had four signal heads on a bracket (or gantry) at the platform end.

 

On other railways, where the signals are placed further apart, it is sufficient to arrange the interlocking so that each signal is interlocked with just the one immediately to the rear. But with signals much closer together (often as little as 50 yards in a station situation), you need the interlocking to work on the next signal back as well to give an adequate braking distance.

In many respects yes.  The GWR (and various other Railways) usually tended to protect trailing points separately although not if they were grouped really close together.  And they almost inevitably had a stop signal immediately protecting the first pointwork at a signal box -as closely in rear of those points as clearance considerations allowed.  One consequence of the relatively high number os signals was that not only was the signal immediately protecting a trailing point locked by that point but the signal in rear of that one was also locked by that point and that became a GWR locking standard.  As layouts were rationalised this could lead to some very odd looking situations such as this view at Ledbury on Adrian the Rock's website - here three trailing point have been removed between the Up Main Starting and Advanced Starting Signals been removed resulting in two successive signals barely 100 yds apart.  The signals have been left like this to minimise the amount of locking alterations required when the layout was rationalised.

 

https://www.roscalen.com/signals/Ledbury/index.htm

 

To give a very extreme example the Up Main Starting Signal at Witham was 5 yards (in linear terms) from the signal box and protected various trailing points.  The Up Main Home Signal was well over 440 yds in rear of the signal box (thus there was a full Clearing Point available to accept an Up train even when a Down train was crossing in advance of the Starting Signal) but it too was locked by the points that the Starting Signal immediately protected.  So in other words, or more correctly GW patois, the signals were locked two back (i.e two stop signals were locked instead of one).  On some Railways you would find a single stop signal placed quite a long way out and protecting points a considerable distance in advance of it  with no other signal immediately in rear of the points.

 

This could incidentally very occasionally lead to a signalling oddity (I was told by a WR locking engineer that there was only one place where it happened on the Western but it could be found at some junctions on ex GNR lines in the West Riding).  In that situation stop signals were locked two back but for traffic reasons it had been considered desirable to make an exception and allow a train to draw forward to teh signal immediately protecting teh junction.  The 'oddity' was that a  si ubsidiary Warning Signal was used to do this - the only occasion on which such a subsidiary was used other than its normal role beneath a Section Signal.

 

So on some joint lines you could find examples of both where two different Companies had been responsible at various times or in different placaes fotr the signalling.  Our Chief Inspector in the Cardiff Division always liked to quote that difference between GWR and LMS 'boxes on the North & West Line.  

 

A rather more complex arrangement was where the GWR did the same thing for facing points which meant that not only was there a splitting signal immediately protecting the points but there could be a similar splitting signal in rear of the actual splitting signal.  To many eyes this could looks as it the rearmost splitting signal might possibly be reading to other routes but that wasn't the case because apart from being a stop signal in its own right it also duplicated (not repeated) the splitting signal at the points.  These duplicating signals had largely vanished during the 1920s and had all gone by the first half of the 1930s.

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Having carefully considered the advice and guidance provided above I have redrafted the track and signalling plan. For explanation, the bay platform is disused for passenger traffic, grey circles are ground signals and a trap point is labelled but not shown due to absence of icon. I hope I have managed to place the signals in the correct places. Any final comments welcome.

Track Plan Signals v3.jpg

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3 hours ago, peterw said:

Any final comments welcome

 

Not directly a signalling comment, but I notice that your sidings are very short indeed.  You might get a more useable length if they were arranged as below (others will correct my signalling).  You'll need to shunt on the main line, or else extend the trap siding offscene to make a long enough headshunt. 

 

I found a plan of Chalford on the Swindon to Gloucester line which makes a possible basis, if you imagine that the sidings on the left and the associated. rossover to the single slip have been lifted.

 

20200511_003019-1.jpg.bd8cf646abda0cd3bc10bf82f2eb7920.jpg

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10 hours ago, peterw said:

Having carefully considered the advice and guidance provided above I have redrafted the track and signalling plan. For explanation, the bay platform is disused for passenger traffic, grey circles are ground signals and a trap point is labelled but not shown due to absence of icon. I hope I have managed to place the signals in the correct places. Any final comments welcome.

Track Plan Signals v3.jpg

Hi Peter,

That looks pretty good to me but get The Stationmaster to sign it off.

I guess engineering trains using the yard would be loco hauled so the need to run round makes sense but just to note that if your operations didn't need to run round or if there was an alternative way to run round, you would only need one crossover.

You could combine the left hand crossover with the turnout to the bay by using a 3-way turnout. Not sure if that helps or hinders, just pointing it out. (Then you would need to stack the relevant discs.)

BTW: Your signal icons are disconcertingly wrong-sided (arms should be to left of post) and see Flying Pig’s more conventional orientation of the icons as if they are facing the driver. Not a big deal, your drawing is understandable regardless.

 

I’m curious about the rest of the layout design: Are there curves outside the area we can see that complete a roundyround plan?

 

Edited by Harlequin
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  • RMweb Gold
14 hours ago, peterw said:

Having carefully considered the advice and guidance provided above I have redrafted the track and signalling plan. For explanation, the bay platform is disused for passenger traffic, grey circles are ground signals and a trap point is labelled but not shown due to absence of icon. I hope I have managed to place the signals in the correct places. Any final comments welcome.

Track Plan Signals v3.jpg

Excellent.  The only thing I would do - which you might like as it saves work ;) - is to regard the trap point as having been removed or at least clipped and spiked out of use and the signal from the sidings reading over it being removed.  This would have been done in the real world when the yellow disc replaced the previous signals from the former bay line in order to reduce maintenance costs.

 

I don't like the idea of a 3 way point suggested by Phil ("Harlequin') as they were distinctly uncommon in WR running lines.  Nothing wrong with having (in the real world =retaining) two crossovers for runround purposes - it didn't always happen but at some places it did happen and with your siding arrangement it is to some extent justified.  I agree with Simon ('Flying Pig') that your sidings are pretty short but there were places in the real world where allowing for a bit of modellers compression of the scene there were some that weren't much longer and I  know of at least one place where the siding was even shorter although it was used for on-track machine maintenance.   You would immediately have a longer siding if you only had one but that might not suit your plans.  Ideally it would be useful to make them a couple of wagon lengths longer but never fill them with wagons - this is a visual trick so a part empty siding tends to make it look longer than it really is.

 

 

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5 minutes ago, The Stationmaster said:

I don't like the idea of a 3 way point suggested by Phil ("Harlequin') as they were distinctly uncommon in WR running lines.  Nothing wrong with having (in the real world =retaining) two crossovers for runround purposes - it didn't always happen but at some places it did happen and with your siding arrangement it is to some extent justified.  I agree with Simon ('Flying Pig') that your sidings are pretty short but there were places in the real world where allowing for a bit of modellers compression of the scene there were some that weren't much longer and I  know of at least one place where the siding was even shorter although it was used for on-track machine maintenance.   You would immediately have a longer siding if you only had one but that might not suit your plans.  Ideally it would be useful to make them a couple of wagon lengths longer but never fill them with wagons - this is a visual trick so a part empty siding tends to make it look longer than it really is.

 

I had compression and increasing siding lengths in mind when I suggested the 3-way.

 

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When the need for traditional goods yards largely died out, typically in the mid to late 1960s, some were certainly retained for engineer's use and, given that in many places the engineer only needed short sidings and that there was pressure to release land for other uses - car parking and/or redevelopment, it was unusual for the retained sidings to be significantly truncated/rationalised. The short sidings proposed here certainly wouldn't look out of place if the scenery was arranged in such a way as to make it look as if the yard had once been much larger but had been truncated - just a modern (for the 1980s) fence across the end might well be sufficient.

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