Signalling help + Interlocking

[Henry.]

I need some help doing signals for my layout. It is a GWR branch in South Wales, originally a random railway company and was probably token?, I assume there would of been an FPL and a home signal out of the platform 

Edited August 9 by Henry.

[Happy Hippo]

More West Wales than South Wales, but if you copy the signalling diagram from Aberayron, you shouldn't go far wrong.

 

A Low resolution diagram courtesy of the Signalling Record Society website:

 

 

 

https://www.s-r-s.org.uk/html/gwm/S2106.htm

Edited August 8 by Happy Hippo

[Jeremy Cumberland]

Your layout doesn't really have any provision to stable a train, including its locomotive, while a second train arrives. I imagine you want to do this (I think it makes a layout more interesting to operate), but where will you put it? Alternatively, if the first train is a passenger train, where will the goods train go when it arrives?

 

If each train always goes back up the branch before the next train arrives, you won't have any signals at all, just a ground frame.

 

Aberaeron has been discussed on here before. Here is a very helpful post describing the SRS diagram linked to earlier: 

On 07/09/2017 at 19:10, 5BarVT said:

Your layout seems to be actual Aberaeron, so is simpler than above. The lever numbers can just be made out on the SRS website http://www.s-r-s.org.uk/html/gwm/S2106.htm. It is a very small and efficient frame. No yellow levers (no Up distant, Down is fixed), 3 and 4 are crossovers, 5 is FPL for 4, 6 is Down Home, 2 is Up Starting, 1 is Up Home OR sidings to main shunt signal. There is no signal protecting the exit from the headshunt/engine shed and I can't see what operates the shunt signal for the run round move. (It may be a point indicator worked with the points, not sure if GW had those.). You will also need a token/staff instrument in the box.

 

[Henry.]

The engines would probably go in the cattle dock siding. I also assume that there would of been a fixed distant signal somewhere down the line

[RailWest]

1 hour ago, Henry. said:

......GWR branch in South Wales, .... I assume there would of been an FPL and a home signal out of the platform....... 

 

Just to be pedantic for the moment, but...red arms are 'Stop' signals. In the position shown that would be a Starting signal, not a Home.

[Henry.]

Sorry, don't really know the names specifically.

[roythebus1]

I doubt a loco would be allowed to berth in the cattle dock, it would frighten the cattle! Similarly a loco would not be allowed to run into the goods shed, fire risk!

[Henry.]

Hmm

[Henry.]

Their might be some room Infront of the goods shed or in the siding or you might be able to put it in the cattle dock

[Jeremy Cumberland]

I wouldn't get bogged down in terminology. @5BarVT called Aberaeron lever 1 "Up Home", and since he knows far more about signalling than I do, I for one am not going to argue.

 

Anyway, @Henry., if the station does have a signalbox, it will almost certainly have a signal more or less where you have drawn it (although your signal appears to be too far to the right - the signal needs to be before the tracks begin to converge). You are also right about needing a distant for incoming trains, which will almost certainly be fixed, but you will also need a home signal for incoming trains before the points (it might be off scene, but this seems a little unlikely to me with this track layout).

 

You are also right about needing an FPL, and this is needed whether the station has a signal box and signals or not.

Edited August 8 by Jeremy Cumberland

[Pinza-C55]

Your best bet would be to find an actual GWR terminus (there were plenty of them) and use the track and signalling layout. I seem to recall a book called GWR Branch Line Termini.

[Harlequin]

This is a standard track plan for a model BLT and it has been signalled many times before.

 

@The Stationmaster Please jump in where I'm getting this simplified explanation wrong:

 

The branch line would almost certainly have been operated using the one-engine-in-steam system, meaning only one loco would ever be in the station at any time. Signalling would have been installed in the very early days of the station. Sometimes the GWR removed it all as an economy measure but most GWR BLTs did retain their original signalling until closure.

 

The signalling controls movements along, onto and off the main passenger-rated line, the line into the platform.

 

In the arrival direction you need a fixed Distant (off scene), a Home signal, which marks the end of the section of track between this station and the next station (the "block section"), and a ground signal to allow shunting from the main line into the loop and the goods yard.

 

In the departure direction you need a ground signal to allow the move from the loco release spur to the loop, another to allow moves from the loop/yard onto the main line and a Starter signal (the one you've drawn) to allow movement from the platform into the block section.

 

Signals should be placed close to any related points but far enough away to prevent vehicles standing at them from fouling alternative routes.

 

[Henry.]

If I'm understanding you correctly this is the signalling layout. The scenic break is the bridge so the fixed distant would be offscene however I don't know if the onto platform / shunt signal would be before or after the bridge

[Henry.]

Would it of been a 10 lever frame?

[The Stationmaster]

2 hours ago, Harlequin said:

This is a standard track plan for a model BLT and it has been signalled many times before.

 

@The Stationmaster Please jump in where I'm getting this simplified explanation wrong:

 

The branch line would almost certainly have been operated using the one-engine-in-steam system, meaning only one loco would ever be in the station at any time. Signalling would have been installed in the very early days of the station. Sometimes the GWR removed it all as an economy measure but most GWR BLTs did retain their original signalling until closure.

 

The signalling controls movements along, onto and off the main passenger-rated line, the line into the platform.

 

In the arrival direction you need a fixed Distant (off scene), a Home signal, which marks the end of the section of track between this station and the next station (the "block section"), and a ground signal to allow shunting from the main line into the loop and the goods yard.

 

In the departure direction you need a ground signal to allow the move from the loco release spur to the loop, another to allow moves from the loop/yard onto the main line and a Starter signal (the one you've drawn) to allow movement from the platform into the block section.

 

Signals should be placed close to any related points but far enough away to prevent vehicles standing at them from fouling alternative routes.

 

My only comment on that very comprehensive reply is that the 'ground signal' for the release crossover would most likely have been a non-independent rotating lamp case - thus saving a lever in the frame as it would be worked off the front stretcher bar in the point.

 

The 'signal box' would probably have been a ground level hut with a ground level lever frame - with or without signal box style windows (styles varied and good example would be the building at Wallingford).  Technically it would not have been a signal box as it would not have been a block post on a line worked on that basis but the name plate would have included the words 'signal box' (typical bit of GWR left hand and right hand at work).

 

As far as Henry's interpretation is concerned the Home Signal should be at the toe of the points leading to the loop and there should be a ground disc (on the ground) alongside it, i.e. co-located.  There were however examples in South Wales, and elsewhere on the GWR, in such situations where a bracket of some description with a short arm would read to the loop but I think that would be highly unlikely in this situation at such a small station with a very simple layout.

 

The lever frame to work it would only need 7 working levers and might possibly have one space giving what amounts to an 8 lever frame.  That would make is smaller than some GWR ground frames in terms of number of levers.

[Henry.]

Just wondering what you mean by 'non-independent rotating lamp case'

[RailWest]

43 minutes ago, Henry. said:

Just wondering what you mean by 'non-independent rotating lamp case'

'Non-independent' means that it was not worked 'independently' by its own lever, but driven directly off the point switch blade.

The style of such things varied between companies, but the early GWR version was essentially one that rotated. The lamp case showed a red light and red face-plate towards the driver when the point was normal, but rotated 90 degrees when the point was reversed to show a green light and face-plate.

[Harlequin]

4 minutes ago, RailWest said:

'Non-independent' means that it was not worked 'independently' by its own lever, but driven directly off the point switch blade.

The style of such things varied between companies, but the early GWR version was essentially one that rotated. The lamp case showed a red light and red face-plate towards the driver when the point was normal, but rotated 90 degrees when the point was reversed to show a green light and face-plate.

 

Also known as a "point indicator". See top photo here:

http://www.gwr.org.uk/no-groundsigs.html

 

The signal for loco release to loop could be either a point indicator or a ground disc, I think - either could be found at various GWR stations. But a point indicator helps if you are trying to reduce the number of levers, as Mike said.

 

Another lever-saving trick is to use "selection", as in the Aberayron diagram above. Just have one lever that operates either the Starting signal or the loop to main ground disc depending on the lie of the loop to main crossover. I.e. which signal the lever pulls off is selected by the points.

 

[Stephen Freeman]

Forgive me but I thought that point indicator ground signals were done away with fairly early in the 20th century as they were frowned upon by the Railway Inspectorate due to the possibility of them showing a safe to proceed indication when they shouldn't (usually due to wear in linkages). Not sure of exact date but possibly some lingered on in a few backwaters.

[Henry.]

How would the selection work, and also would you use the shunt or the stop signal for running around?

[Henry.]

Do you think I will run straight into the loop often as usually I will probably run to the platform and do shunting from there?

[Henry.]

It would also be good if anyone had any advice about interlocking for this plan

[The Stationmaster]

1 hour ago, Stephen Freeman said:

Forgive me but I thought that point indicator ground signals were done away with fairly early in the 20th century as they were frowned upon by the Railway Inspectorate due to the possibility of them showing a safe to proceed indication when they shouldn't (usually due to wear in linkages). Not sure of exact date but possibly some lingered on in a few backwaters.

The one at our local brancj junction remained in situ, and occasional use until c.1960/61.  They were still around on  release crossovers at some places until either dieselisation/removal of the crossover, or line closure or - in a few cases until 1950s resignalling schemes although I've no doubt quite a few went in the various GWR modernisation and layout changes in the 1930s.release crossovers.

 

27 minutes ago, Henry. said:

Do you think I will run straight into the loop often as usually I will probably run to the platform and do shunting from there?

 

Exactly so.  Lots of modellers seem to get the idea that freights would run into the loop rather than the platform line at a branch terminus but they are well wrong except at those places where the loop was signalled for that purpose (not many).  The reasons for running to teh platform are twofold -

1. It provides the longest length for running round a train on most branch terminus track layouts, and

2. The normal signalling arrangements meant that the train would be accepted towards the platform line.

 

But you need the ground disc by the Home signal once you start shunting wagons off your freight train after the engine has run round the train.

[Michael Hodgson]

1 hour ago, Stephen Freeman said:

Forgive me but I thought that point indicator ground signals were done away with fairly early in the 20th century as they were frowned upon by the Railway Inspectorate due to the possibility of them showing a safe to proceed indication when they shouldn't (usually due to wear in linkages). Not sure of exact date but possibly some lingered on in a few backwaters.

 

Yes, point indicators driven off the point rodding were very common in the Victorian era and fell out of favour about the turn of the century.  However there was no requirement to replace them generally, and some lasted quite a long time.  If it ain't broke, don't fix it.   A disc would probably be susbtituted during a complete resignalling which seems unlikely here unless  the locking frame itself needed replacement because of wear.  In any case the risk was minimal for an engine release crossover beyond the platform at a terminus - the risk would be higher for example at a siding exit signal leading onto a running line.

[Michael Hodgson]

2 hours ago, Harlequin said:

 

Another lever-saving trick is to use "selection", as in the Aberayron diagram above. Just have one lever that operates either the Starting signal or the loop to main ground disc depending on the lie of the loop to main crossover. I.e. which signal the lever pulls off is selected by the points.

 

Selected signals were usually provided where a layout had been expanded, all the spare levers had been used, and so you appeared to need a longer lever frame, and probably also an extension to the building.  The locking of such signals is more complex and they need more maintenance, so you probably wouldn't usually design it in at the outset, so I don't think that's likely here.

 

50 minutes ago, Henry. said:

How would the selection work

 

There is a mechanical linkage operated by the point lever which allows one or or the other signal to work.