A signalling challenge

[rovex]

Whilst I'm along way off building this end of the station I thought it would be good to get an idea of what lies ahead for me.

 

Attached is the a screen print of the North end of Brackhampton Snow Hill, would anyone like to advise as to how it should be signalled. It's based, as anyone who has been following my blog will know, on Birmingham Snow Hill, but its been simplified (no honest it has) and although I have some plans of the original but as I've simplified it it may not be appropriate to follow the plan I've got which is actually fairly small and rather difficult to make out in any event (well it is to me)

 

For anyone who doesn't know the layout of Snow Hill, I should explain the approach tracks from left to right are "Up Main, Down Main, Up Relief and Down Relief.

The platforms from top to bottom are

 

Top track (platform 11/12 - the long platforms had two numbers and could hold two full length trains - I'll hopefully manage two local trains or one full length express)

 

Next two - Bay platforms 10 and 9.

 

Then Platform 7 and 8 (for which the expresses to Paddington usually left)

 

then two through tracks (which each had a pair of scissor crossings which were controlled by ground signals)

 

Then platform 6 and 5 (for which trains to Wolverhampton left)

 

Two more bay platforms 4 and 3

 

and then at the bottom platform 1 and 2.

 

Trains coming from the North on the Up relief can access almost any platform (except 6 and 5), trains entering on the Up Main can access platforms 7 through to 12.

 

Trains on leaving from platforms 12 through to 9 and 6 and 5 can leave on either the Down Main or Down relief.

 

Trains on platforms 4 through to 1 can only leave on the Down relief.

 

Period is 1950 so before the station was resignalled - so its all semaphores I'm afraid.

 

I'm not so worried about the Southern End of the station as most of the track work is either under the overall roof or underneath the City Centre.

 

Oh if anyone wants a larger plan to work on , just let me know

 

So there's challenge should you choose to accept it.

 

Thanks guys

[beast66606]

Remember trap points ...

 

Nothing hard about most of the signalling,

 

For arrivals

you can put an approach home over the 2 up lines, a main arm, a call on and a route indicator of some form - a theatre, with 2 boxes, showing 1 - 11 or example.

 

For departures

Each platform needs a main arm for each of the down lines it can take, most will have 2 arms, 1 - 4 will have 1 arm.

Some need additional shunts for the sidings - such as Platform 1/11/12 (and there are more)

 

That's the easy bit, the difficult bit is deciding on how you intend to operate it and therefore where shunt signals should go, frequently at bigger terminal stations there would be shunt signals positioned around the layout to allow engines to run out of the platforms and then setback onto trains - for example you have a piece of clear line near to the end of the siding which runs off P5/6 - this could be a position where locos run to before setting back into P5-11. The easier alternative is to assume all shunts either run into sidings or go beyond the throat, they can either shunt out wrong line and use the approach homes to return to the platform road or they can shunt out right line and you could have ground signals controlling their moves back into the platforms.

 

How much space do you have in the middle of the point work for engines to stand ?

[rovex]

Thanks Beast, whilst not a novice at railway modelling, signalling is one of those things I have always struggled to understand. I've previously got round this by not bothering with any like most modellers, but this time I wanted to have a go at getting it right - well reasonably right.

 

This link http://www.warwickshirerailways.com/gwr/gwrbsh1167a.htm, is to the only source (other than historic photos) which give some kind of indication as to the signalling arrangements - although without a knowledge of signalling practice and local operations it is not readily (to me at least) obvious as to what signal controlled what line - I'm thinking of the bracket signals particularly in this respect.

 

There are a couple of things I would like to model, such as the bracket arm which sprouted from the canopy on platform 6/5 which controlled the down through road and - I think - trains departing from that part of platform 6/5 that was under the overall roof.

I wasn't intending parking engines between the points on platforms 3/4 or blocking any of the main lines with engines. Generally trains will arrive and depart, or terminate and then be disposed of, engine probably to offsite depot and carriages (probably in the other direction to offsite carriage sidings. Freights would come through on the up or down through roads. Suburban stock may be shunted to the three short carriage sidings (many photos of the station show plenty of suburban coaches being "parked" here during a lll between rush hours.

[beast66606]

This link http://www.warwicksh...gwrbsh1167a.htm, is to the only source (other than historic photos) which give some kind of indication as to the signalling arrangements - although without a knowledge of signalling practice and local operations it is not readily (to me at least) obvious as to what signal controlled what line - I'm thinking of the bracket signals particularly in this respect.

 

The bracket to the left of the box has arms for both the up and down main lines

 

There are a couple of things I would like to model, such as the bracket arm which sprouted from the canopy on platform 6/5 which controlled the down through road and - I think - trains departing from that part of platform 6/5 that was under the overall roof.

 

Not a problem, you will need the signal anyway, so you can model the actual one

 

I wasn't intending parking engines between the points on platforms 3/4 or blocking any of the main lines with engines. Generally trains will arrive and depart, or terminate and then be disposed of, engine probably to offsite depot and carriages (probably in the other direction to offsite carriage sidings.

 

Not a lot of shunt signals required then.

 

Freights would come through on the up or down through roads. Suburban stock may be shunted to the three short carriage sidings (many photos of the station show plenty of suburban coaches being "parked" here during a lll between rush hours.

 

Again not a problem.

 

 

The link shows the signalling using fairly common GWR practice, (waits for StationMaster to shoot him) with intermediate routing signals, the bracket mentioned above is one example, the main signals controlling trains arriving from the left have one or two routes, these lead to a second signal which has the rest of the routes.

 

The linked plan does not look to be correct, so don't take it as gospel.

 

I could knock something up over the next few days if you like ? - based on the actual.

[The Stationmaster]

You could always invest in the SRS disc (they were at Warley last year) and get a decent scale copy of this

http://www.s-r-s.org.uk/html/gwr/S2832.htm -it's even better at Western signalling for Snow Hill than I would be but if you can send me a larger copy of your drawing I can do it in Western fashion for you.

[The Stationmaster]

 

The link shows the signalling using fairly common GWR practice, (waits for StationMaster to shoot him) with intermediate routing signals, the bracket mentioned above is one example, the main signals controlling trains arriving from the left have one or two routes, these lead to a second signal which has the rest of the routes.

The linked plan does not look to be correct, so don't take it as gospel.

 

Snow Hill was a little unusual (on the GWR) for having a change of pairing in the north end throat. To the north the running lines were paired by use, through the station the through lines were basically paired by direction with an upside island platform and a downside island platform although both had north end bays that could both terminate and start trains. From a quick peruse that linked plan is right - but complex.

[rovex]

Hi Stationmaster, if you've got templot I can send you the box file.

 

thanks

[The Stationmaster]

Hi Stationmaster, if you've got templot I can send you the box file.

 

thanks

Alas no Templot (not so keen on a Mac I believe) but a JPEG would be quite ok if you can save it like that. Have you got the relevant SRS disc or are you working off the stuff that Beast has quoted (which we've looked at before fro other things I seem to recall)?

[Colin4d]

In a loco relase loop, where a train is uncoupled at the end of the platform before running round the train, would the shunt/GPL signal show two possible routes, or just the one for running round the train?

 

Would a loco that was uncoupled and left at the end of the platform whe the coaches were removed by another loco need a shunt signal to release it if it didn't run round the train?

[beast66606]

In a loco relase loop, where a train is uncoupled at the end of the platform before running round the train, would the shunt/GPL signal show two possible routes, or just the one for running round the train?

 

If a signal was provided it could be either, depending on requirements.

 

Would a loco that was uncoupled and left at the end of the platform whe the coaches were removed by another loco need a shunt signal to release it if it didn't run round the train?

 

Yes or No.

 

Liverpool Lime Street had locos which used to sit on the stops and had no signals to allow them to run to the main signals, all done by phones.

 

 

As it's a real place you already have your signalling though

[TheSignalEngineer]

Admittedly in DMU days, but Birmingham Moor St had a local instruction that trains were to remain on the stop blocks until the platform end signal was showing a proceed aspect. This was to give the signalman the option of putting a second train in and out while the first one was still there.

 

I don't know if this existed when trains were loco worked.

[Colin4d]

I'm quite interested in this, but in more modern times when routes are set between signals.

If the loco was running round the train and had to pass a main starter signal, for example on another platform, would a route be set from the shunt/GPL at the loco release end to the starter signal, then another route set from the starter signal to another signal beyond the starter, or would a separate shunt signal be provided to allow the route to be set without clearing the main signal?

 

If no signal existed at the point where the loco running round would stop and change direction to couple to the carriages, how would a route be set? Can you set a route from a signal to a limit of shunt?

[micknich2003]

Yes, you can set a route from a signal to a Limit of Shunt, there was one, for example at Hessle Road Hull, where I once worked. From memory a similar example exists also localy at Beverley. Another local example was once to be found at Bridlington Quay, where following PWay alterations an existing mechanical disc was disconected and left in situ as a "LoS" board. Mick Nicholson.

[phil-b259]

 

If no signal existed at the point where the loco running round would stop and change direction to couple to the carriages, how would a route be set? Can you set a route from a signal to a limit of shunt?

 

In signalling terms a LOS is a signal - just one that cannot show anything other than Red - a buffer stop lamp is also technically a signal by the way. Thus when setting a route from a signal to a LOS / Buffer stop you are setting it fropm a signal to a signal. Of course over the years LOS have taken many forms which can range from a very wordy sign through to a modern shunt signal that can only show two reds. As the mick said it is also possable to get the situation where a previously working shunt becomes a LOS by fixing it at dangerbecause of layout changes

[Colin4d]

So in this simple layout a train arrives at Platform 2. The loco uncouples to run round and moves forwards to the buffers of P2.

 

A route is then set from S100 to S2 and the loco reverses via Platform 1.

 

A route is set from S2 to the LOS signal

 

Once at the LOS a route from S103 to the buffers of P2 is set and the loco couples on to the carriages.

 

 

Is this how it would work?

[micknich2003]

You don't need the "Sub" 101 to take you through the Cross Over, it would be a Route Indicator on the main signal. I can't see any reason why you should need to Shunt Out" behond "S1" signal. It is not convention to have an "LoS" board in the normal direction of traffic. Think about it, every train leaving the station, would stop at it and proced no further. As already mentioned an "LoS" is effectivly, a signal fixed at "Danger". Best Wishes, Mick.

[TheSignalEngineer]

There would be no LOS on a right direction shunt on a running line. An LOS would only be required if the shunt went out wrong line behind S101 to stop it short of a train at S1.

 

In multple aspect signalling signal S101 would be automatically cleared by setting a route from S1 to a platform road.

 

(Mick is beating me to it here as I type)

 

S2 and S4 would have a shunt aspect to read up to the LOS behind S101 if it were provided, otherwise could use the main aspect to go behind S103.

[Grovenor]

So in this simple layout a train arrives at Platform 2. The loco uncouples to run round and moves forwards to the buffers of P2.

A route is then set from S100 to S2 and the loco reverses via Platform 1.

OK so far.

A route is set from S2 to the LOS signal

No, there would not be any LOS on the departing running line, the end of the route from S2 would be the next main signal.

Once at the LOS a route from S103 to the buffers of P2 is set and the loco couples on to the carriages.

OK here.

 

An LOS will always be found on the arriving line as its purpose is to prevent trains accidentally departing on the wrong line.

In this layout there is no need to shunt on the wrong line so no need for an LOS and no need for S101.

 

Other things being equal (eg location of main station facilities etc) I would reverse the release crossover so loco hauled trains arrive in P1, If needed trains could be shunted into P2 to await departure or P2 used just by MUs.

Regards

Keith

[phil-b259]

So in this simple layout a train arrives at Platform 2. The loco uncouples to run round and moves forwards to the buffers of P2.

 

A route is then set from S100 to S2 and the loco reverses via Platform 1.

 

A route is set from S2 to the LOS signal

 

Once at the LOS a route from S103 to the buffers of P2 is set and the loco couples on to the carriages.

 

 

Is this how it would work?

 

Not quite. Remember a LOS is a red signal for all trains regardless of their type, so putting where you have done on the diagram means nothing can depart from the station!

 

In the run round situation you describe the route would be set from signal S2 to the next signal on the departure line which is not shown on the diagram. Signal S2 would change to a preceed aspect and the loco would run onto the departure line and even though it will have a whole signal section avalabel the driver will know he only has to go far enough so that he clears the pointwork and is standing behind S103 signal. Then the route is set from S103 signal to the buffer stops allowing the loco to rejoin its train.

 

The LOS only comes into play should you wish to do the above move via the arival line instead. In this scenario the loco proceeds from Signal S2 onto the arival line. As this is a wrong direction move and to prevent the driver from going to far and endangering a train standing at or approching signal S1 a LOS is provided at a suitable distance from the pointwork. Also it follows that because of this the distance between signal S1 and the station must be extended to compensate for the length of track between S101 and the LOS which may now be holding a loco and cannot form part of the overlap for signal S1. Anyway with the loco now standing behind signal S101 the route is set back into the station.

[The Stationmaster]

Believe it or not there is a situation in Britain where there really is a facing LoS!!! However it is on a leisure/heritage railway although their signal engineer was slightly red-faced when I pointed it out to him during an IRSE visit a couple of years back. BUT IT IS NOT A PRECEDENT.

[phil-b259]

The LB&SCR had facing LOS indicators that were mechanically operated to show a 'clear' indication. There's a photograph of one at Horsham in George Pryer's book on Southern Signals.

 

Much more recently, there used to be a facing LOS on the Down Main at Motherwell. Its two red lights were extinguished when a main route was set beyond it.

 

Interesting, although you could say that in the former caes it behaved more like a shunt signal and in the later the LOS has been 'removed' when not required which is a bit different from it still being present and drivers simply ignoring it when required (Which must be the situation with the one discovered by Mike)

[The Stationmaster]

 

Interesting, although you could say that in the former caes it behaved more like a shunt signal and in the later the LOS has been 'removed' when not required which is a bit different from it still being present and drivers simply ignoring it when required (Which must be the situation with the one discovered by Mike)

Indeed Phil - the Goodrington one is not suppressed (unless it''s been rewired although I doubt that as the new controls were only just being finished when I took that pic).

[rovex]

Does anyone have any thoughts on a signalling plan for the layout though?

[The Stationmaster]

Does anyone have any thoughts on a signalling plan for the layout though?

The layout sketch is sitting on my desk waiting for the signals to be added (ex GWR 1950 as I understand things) with one query - is it a slip or a diamond where the line from Platform 4 crosses that from Platform 3 to access the siding on the Down side?

[rovex]

Thanks,

 

Its a diamond.