Is this signal plan feasible?

[Kinighit]

Hi, I've devised this plan of a layout I have and I'm stuck with the signalling side.

I've spoken to a few individuals and this is what they have surmised as a feasible signal plan, but something doesn't feel right and I'd like some more people to have a look and advise accordingly.

 

This is meant to be depicting a non prototype station/depot based in the North West, time period is post Tops, so signals are lights. It's bi-directional running between the scissors but purely for access to the yard at the top and  storage sidings at the bottom left. Typically I'd like passenger running through the station as normal but if it would need to be altered (signal wise) please let me know.

 

If this was used in a lever frame signal box would it be correct ie, 12x facing point locks (blue), 31x stop signals (red levers as are shunters signals (plan has green for stop purely to differentiate)).  White spares, brown level crossing, yellow distant signal and 20x black for points.

 

Ok I know the yard and the sidings would be ground frames as its easier for shunting duties, but if they were in a signal box.

 

Would a scissor have two levers to operate a pair of points (like we would do for a switch for the point motors) or four individual levers.

 

Any help would be appreciated as this has been boggling my head for over a year and I'd like to have it addressed while I'm off.

 

Thanks people.

 

[Jeremy Cumberland]

The main lines are straightforward. Starters at all the platform ends used by departing trains, which from your description is the right hand end of the both top platforms, the left hand end of both bottom platforms, and the right hand end of one of the bottom platforms for trains coming from the sidings. The approach lines to the station will each need a home, possibly with route indicator, before the scissors crossover is reached (yes, I know they aren't called homes and starters in this era). The "homes" may, of course, be outside the area shown by your plan, but I would be inclined to put them just before the crossovers, and then the shunt signals can be subsidiaries. I think it is rare for there to be ground signals on main lines in the normal direction of travel. Alternatively, all shunting movements over the crossovers could be conducted onto the opposite line, so the shunt signals to head back to the station are not faced by oncoming main line trains, but this would probably be unduly restrictive, particularly at the right hand end of the station.

 

The sidings are rather a problem. How is shunting carried out? Where's the protection from the main line? How can trains be signalled into the sidings with any confidence that the line is clear? How do trains run round? Why, in any case, are the sidings in the facing direction off a main running line - I don't think any railways favoured this arrangement? There is an obvious solution to all of these questions, by having the sidings coming off the bottom platform road. There would then be an arrival line, track circuited and controlled, with a shunt signal and trap point on the exit from the sidings proper, and a subsidiary on the platform starter for trains coming off the main line. Run rounds could be done in the station - a little inconvenient operationally, but at least it could be done.

 

I imagine the controlled area of the shed would just be the length of each crossover. Each would need a shunt signal on exiting the shed, as close to the shed as possible, with a trap point beyond. No other signals would be needed to exit onto the main line.

 

What shunting movements would there be? Run rounds at the bottom platform for trains going in or coming out of the sidings. This would need subsidiaries on the platform starters, and the obvious arrangement to me would be to run the locomotive out to the far side of the scissors crossover where there is already a shunt signal, back along the second platform road from the bottom, which will therefore need a subsidiary on the starter at the left hand end and a shunt signal at the right hand end. At the other end of the platform, the locomotive again goes to the far side of the scissors crossover, although at the left hand end you could have a ground signal just beyond the platform loop points.

 

Locomotives entering the shed from the main running lines could be admitted via the subsidiary signal just before the scissors crossover. Locomotives entering the shed from the sidings would need to be signalled out beyond one or other of the scissors crossovers, where there are already shunt/subsidiary signals for coming back in.

 

This gives, by my count, two "home" signals with subsidiaries, five "starters", three with subsidiaries, a shunt signal at each of the scissors crossovers for coming back into the station from the "wrong" line, although I am not entirely convinced that the one at the right hand scissors crossover is needed, and the one at the left hand scissors crossover could be replaced by a shunt signal at the left hand end of the bottom platform loop. You also need a shunt signal at the right hand end of the bottom but one platform and three shunt signals to control the exits from the engine shed and the sidings, each with a trap point.

 

In terms of FPLs, the left hand entrance to the engine shed definitely needs one, as does the sidings entrance. My guess is that the other shed entrance points would have an FPL as well.

[Kinighit]

Thanks Jeremy C,

 

I had wondered about a Modratec Interlocking Frame, the SigScribe4 software is crap (like Hornby's elink) to work with so it's easier to make a linear plan.

This is where this plan comes from.

 

The mainline on the left curves around the back of the engine shed on to an incline which disappears 90degress to the top (reverse S), the sidings are in the space left over.

The mainline on the right also curves around but behind the smaller shed. 

Hopefully this will clarify the reasoning. I will try and design the actual layout in Scarm to edit it.

 

 

If I read this right, the "Home" (3 way aspect) with route feather and shunters signal, at either end prior to the scissors coming into the station.

 

A shunters signal on the scissors, opposite lineside to the "home" signals.

 

3 FPL's coming out of the shed area and sidings

 

5 starters (although I was lost on which should have the shunters on)

 

A shunters signal coming out of either side of the shed area.

 

A shunters signal coming onto the main line from the bottom platform.

 

I'll also try and get a picture of the actual layout which will show better, but its in storage at the moment.

 

thanks again for your help.

[Flying Pig]

15 minutes ago, Kinighit said:

 

3 FPL's coming out of the shed area and sidings

 

AFAIK, you need facing point locks on all points over which passenger carrying trains run in the facing direction.  So, assuming you don't want to have bi-directional running through the platforms, you will need:

 

- right to left main line: facing point on scissors; entry to platform loop; entry to sidings; facing point on scissors;

 

- left to right main line: facing point on scissors; entry to platform loop; facing point on scissors;

 

- left to right platform loop: facing point into shed.

 

You don't need FPLs on trailing points, or on the sidings side of crossovers.

 

BTW, there is an interesting page on the s-r-s site showing diagrams for Stockport No.1 and No.2 in 1976.  These are mechanical boxes controlling a colour light installation, fortuitously in the North West, and seem to confirm @Jeremy C's suggestion that the main signals should be on the platform ends and outside the crossovers, with associated subsidiaries for shunting moves.  However, route indication for the 'homes' seems to be by theatre indicator rather than feather. I think the subsidiary position lights would have their own stencils but I could be wrong there.

 

There are also some discs for reverse shunting movements, but none that would be passed by running movements in the right direction so far as I can see.  Your sidings are a bit of a fly in the ointment here and I think the exact setup would depend on how far they are from the platform end and what they are used for.

[Kinighit]

This is the shape of the layout

Edited August 1, 2020 by Kinighit
Phone didn't upload

[ikcdab]

Ref the scissors. If this were my layout, I would control all 4 points from one lever or switch.

[Kinighit]

21 hours ago, Flying Pig said:

 

- right to left main line: facing point on scissors; entry to platform loop; entry to sidings; facing point on scissors;

 

- left to right main line: facing point on scissors; entry to platform loop; facing point on scissors;

 

- left to right platform loop: facing point into shed.

 

Right I have added the signals to the actual layout plan that Jeremy C suggested and I've added the FPL that Flying Pig suggested. The brown lines are an embankment which i why the sidings are "tucked away"

 

Hopefully this makes a bit more sense.

[Wheatley]

As can be seen in the Stockport example, colour light signals and manual points are feasible. The two scissors at Stockport are both worked differently - one has a lever for each end, one has adjacent ends worked off the same lever, I suspect the reason has something to do with the black art of mechanical interlocking but there's no reason on the model why you can't throw all 4 ends at once off one lever/switch if your CDU is up to it. 

 

If you modernise the Stockport example a bit further and introduce motor points then you don't need any FPL levers at all as motor points are self locking. For any hand points in the yard I would put them on a separate lever frame distinct from the box frame. My BLT has the signalbox frame numbered 1 - 6 and the separate hand points frame alongside lettered A-E. 

[Jeremy Cumberland]

The scale track plan makes a lot more sense.

 

Entrance to the sidings is going to be a problem. What are the sidings used for? If they aren't track circuited with motorised points and signals for each siding (possible for carriage sidings, but unlikely I would have thought for anything else) then I think trains wishing to enter them would have to be stopped at the points before the points could be reversed. This is because there is no guarantee that there is an empty siding for the approaching train (and no guaranteee of which siding the points are set for), and a train cannot be signalled straight into a potentially occupied line.. This could mean having a main signal with siubsidiary (which I think would be fine here; visially it is a long way from the station, even if it isn't in feet). Alternatively the points could be worked from a local ground frame released by the signalbox, in which case there probably wouldn't be any signals at all, either to enter or leave the sidings.

 

Much the same is true of the shed entrances; the entrance roads are shorter than I imagined. Trains approaching from the right might not be a problem; the subsidiary signal at the scissors crossover isn't so far away, and I think this signal is only used for trains entering the shed, but there is no guarantee that the shed entrance road is clear, apart from the short length before the shed exit signal which would be track circuited.

 

In the other direction, though, the shed entrance is a long way from the subsidiary at the scissors crossover, so I would be inclined to place a main signal with route indicator and subsidiary immediately before the first set of points entering the station. Trains for the shed, which up to this point have been signalled using main signals, would be stopped at this signal before the points are set for the shed and the subsidiary cleared. It ought to be three aspect and show a yellow to trains entering the station when the starter is red.

 

Other signals depend very much on what shunting and running round you want to do, and whether you want any trains to reverse in the platforms and leave in the direction they arrived from. At least one of the bottom platforms needs a starter at the right hand end for trains coming out of the sidings and continuing in that direction.

[Kinighit]

I've just realised my last post never included the diagram (Stupid phone). I've included the other signal with feather coming into the station.

 

The sidings are subjective at the moment, I'm not sure of a small NR yard (ballast and rails) or DMU/coach storage as the main shed is meant to be a bit like Eastleigh with various locos being maintained.

 

Wouldn't Severn Bridge Junction also be mechanical operating electronic lights?

 

Again thanks for all the help, as you can see it's not an easy design. (I had though of sending it to NR and let them try and work it out! lol)

[BusDriverMan]

Can you squeeze in a headshunt around the top left curve, and change the connection to a trailing connection on the other side of the scissors?

 

 

This eliminates the facing point and lets the last siding act as a headshunt / catch point to stop runaway trains going straight into the Down main line.

 

Trains arriving and departing from the station on either line will both need to reverse on the Down main line. With the original design, there's direct access to the Down platforms, but getting to the Up side of the station requires two reversals on the main line to use the Down scissors, or travelling right through the station to use the Up scissors.

 

The yellow subsidiary signal in the yard before the crossover to the main line only applies to travel over the crossover - movements in and out of the down headshunt / last siding are unsignalled. I'd imagine the crossover and the two signals next to it would be controlled by a ground frame released by the main signalbox.

 

The two Down signals next to the scissors might be redundant - the  platform starters could do the job. I've sketched in subsidiary signals for travelling onto the Up line to reverse at the Up signal by the scissors crossover - the Limit Of Shunt signal (fixed red subsidiary signal) stops the train running on the wrong line all the way to Holyhead. Alternatively they could be eliminated, and trains would reverse at the subsidiary signal by the Down yard crossover to access a different part of the station.

 

There might need to be route indication on the Down line subsidiary as routes can be set from it straight into the Down yard or any part of the station. In which case, I'm not sure how it'd be operated - the signaller would clear it for routes into the station and the Up yard, while the shunter would clear it for routes into the Down siding? Doesn't seem insurmountable.

 

I was procrastinating yesterday and found a fascinating document on the RSSB website (while googling for something else entirely) - "Signalling and Operational Telecommunications Design: Technical Guidance". A 327-page PDF written by Railtrack in 1999 and filled with far too much detail even for me - but on page 199 there's signalling diagram for a fictional junction station with multiple-aspect signals controlled by a lever frame and a description of the interlocking, followed on page 273 with the same location but with relay interlocking and NX panel control. Found it quite interesting!

[Kinighit]

I've managed to get the layout out (Indiana Jones would have been proud at the tasks involved). Here are the photos. I've managed to get the layout out (Indiana Jones would have been proud at the tasks involved). Here are the photos.

[Kinighit]

The boards are 4'x3' each giving a length of 8'. The large area at the top is for the station building, car park etc. The idea is to have full length HST's.

 

[BusDriverMan]

Oh nice! Didn't realise the layout already exists despite the first sentence of your first post… d'oh

 

Incidentally - if there's colour light signalling, there's probably also power-operated points. Point motors almost always have a facing point lock built in, so if you're controlling this with a lever frame, you wouldn't need FPL levers.

Edited August 8, 2020 by BusDriverMan

[Jeremy Cumberland]

It's nice to see the layout, and I can understand why some decisions were made. It isn't easy thinking how to signal an already-existing layout; for prototypically-correct signalling, you really need to think of the signalling first and design the track plan around it, but I think you can have quite good signalling arrangement here.

 

I think the biggest decision is whether to have main signals immediately before the points for the platform roads. Given the distances involved, I think the answer is yes, and this resolves one of the awkward questions: how to signal up trains into the shed (using up and down as per @BusDriverMan's diagram). The alternative would be to have a ground signal immediately before the shed points, which would also need to be cleared for trains using that platform. However, I'll assume you have a main signal.

 

In the up direction, there is a main signal with subsidiary before the scissors crossover. If you want up trains to use the down platforms then the signal needs a route indicator for the crossover (feathers, probably). The subsidiary is primarily for access to the sidings. I suppose if you have a main signal over the crossover, then you don't need a subsidiary, although it might allow more flexible working if both down platforms are occupied (depending on how prototypical you want the operating to be).

 

Continuing in the up direction, there is a main signal with subsidiary and route indicator (feathers or theatre) immediately before the platform points. The subsidiary signal is primarily for trains entering the shed, but it could also be used for any shunting or run round moves.

 

If the down platforms are also used for up trains (apart from trains leaving the sidings) then you should have a main signal and subsidiary at the down platform points as as well. The subsidiary is for running round, which will presumably be needed for trains coming out of the sidings. If you don't have a main signal here, just have a ground signal.

 

The up platforms each need up starters, as do whichever up platforms you want to use for trains exiting the sidings. To my mind it makes sense to signal both down platforms for up trains. Assuming you will be running round in the down platforms, the up starters need subsidiary signals. If you aren't running round or releasing engines in the up platforms then subsidiaries aren't necessary. There are no further signals in the up direction on the up running lines.

 

The down direction is almost a mirror image of the up direction. Provide a route indicator at the signal before the sicssors crossover if you want to allow main line trains into the up platforms, but if not, provide a subsidiary signal for locos going into the shed. Provide down starters on the up platforms only if you want to signal down main line trains this way.

 

An additional signal is needed on the down line, immediately before the sidings points. This has a subsidiary for entry into the sidings.

 

The sidings exit and both shed exits are controlled by ground signals,

 

For shunting operations, running round in a pair of platforms requires six shunting signals (either ground or subsidiary), and I have already mentioned these. There should be one at each platform end, either as a subsidiary to the starter or, if there isn't a starter, as a ground signal. There should also be a signal at each facing point for the platform roads.

 

Movements between the shed and the up platforms use these same signals.

 

The only other shunting you need to allow for is movements between the shed and the sidings or down platforms. Here you need to use one or other of the scissors crossovers. If movements are always made wrong line (so locomotives from the shed going to the sidings, for example, remain on the up line till they are beyond the crossover, then reverse across the crossover to the down line, then reverse again into the sidings), then you already have signals to control this movement, and all you ought to do (if it is within the scenic part of the layout) is to add a limit of shunt indicator.

 

If you want this shunt to be carried out right line, so the locomotive from the shed uses the crossover to move onto the down line, before reversing along the down line and reversing again into the sidings, then you need a ground signal on the down line by the crossover, to control the movement back towards the station. I expect you will copy the same arrangement at the other end of the station.

[Kinighit]

Thanks again for all the help and input. 

 

This plan should be what you described, if not please correct me/it.

 

I think I've followed everything you've said about the main lines, Jeremy C, up to the shunting operations, then I got a bit lost lol.

 

But I think from what you guys have been saying, on the right hand side crossover on the down line going to the up I need a shunt signal and maybe a main on the up side to cover that manoeuvre ?

On the left hand side crossover, on the up line there should be a main and subsidiary to cross over and protect the same from the other side?

 

I wasn't going to use both of the Down platforms but I think it will give me more operational options from the sidings. The Up platforms won't need to be used (I don't think).

 

Also won't I need signals coming out of the sidings and the yards?

 

Edited August 9, 2020 by Kinighit

[Jeremy Cumberland]

10 minutes ago, Kinighit said:

But I think from what you guys have been saying, on the right hand side crossover on the down line going to the up I need a shunt signal and maybe a main on the up side to cover that manoeuvre ?

 

Heading away from the station, I don't think any signals are needed at the right hand crossover, because the signal controlling the movement from the station or the shed will also cover any movements over or past the crossover, The only possible exception I can see is approaching this crossover on the down line, where the addition of a ground signal would allow a little more flexibility in run round movements (which don't need to use or go past the crossover at all).

 

If a locomotive or train has to go from the down platforms to the shed (or vice versa) via the right hand ctossover, you need a signal for the movement back to the station. If this movement is via the up line, you need a ground signal. If this movement is via the down line, then there is already a signal for the movment back into the station so no additional signal is required, but you would need a limit of shunt indicator further along the down line (probably beyond the scenic area).

 

The same thing applies at the left hand crossover, except here there is an additional signal heading away from the station, just before the sidings points. The subsidiary signal here can be used for several different movements:

1. Entering the sidings
2. Continuing along the down line past the crossover, prior to reversing back over the crossover to the shed.
3. Crossing over to the up line prior to reversing back to the shed.

27 minutes ago, Kinighit said:

Also won't I need signals coming out of the sidings and the yards?

Yes. For the sidings, if the points within the sidings are hand-worked (usual except sometimes in the case of carriage sidings), then you need just one exit ground signal. If the sidings points are motorised (and in the prototype would be track circuited) then you need individual exit ground signals for each siding. Whatever arrangement you use, trains only pass one signal when exiting the sidings.

 

For the shed, I cannot imagine the pair of points between the turntable and the shed roads being motorised, so you just need an exit signal on each of the two exit roads.

[Kinighit]

Ok making more sense now.

Revised the track plan again added the LoS, ground signals to the sidings (if coaches) and the exit signals of the yard.

 

So am I correct in thinking that the left hand yard exit signal will cover the up main line all the way to the LoS on the slope and I won't need the main or subsidiary signal before the crossing (which I've left in for the moment)?

 

How can the subsidiary signal before the sidings do both left and right points, wouldn't I need 2 subs?

 

I've also highlighted the shed in this plan, beneath it on the plan, I'm thinking of putting a diesel fuel point (blue) between the 2 sidings. The furthest bottom siding being for rolling stock waiting for the depot. The top sidings will also be storage and the top siding closest to the depot will have a train wash.

 

Looking at other depots there seems to be starter signals on all lanes, would that be employed here maybe?

 

Sorry to be a pain, I'm due to leave for the RFA next month and this has been bothering me for years, lol

[Jeremy Cumberland]

At the sidings exit, I don't think there is any need for a main signal. If the route isn't clear onto the main line, the individual siding signal would not be cleared because there is nowhere else for the train to go. A main signal tells the driver nothing that ground signal does not tell him or her.

 

30 minutes ago, Kinighit said:

So am I correct in thinking that the left hand yard exit signal will cover the up main line all the way to the LoS on the slope and I won't need the main or subsidiary signal before the crossing (which I've left in for the moment)?

It's up to you really. If every train leaving the shed in this drection has to go beyond the scissors crossover, then the shed exit signal can cover the entire movement. If some movements don't need to go this far then a shunting signal here would be a very good idea, so the crossover is not tied up unduly for movements that do not require it. However you do it, I don't really see a need for a main signal, nor for a main signal exiting the shed.

 

35 minutes ago, Kinighit said:

How can the subsidiary signal before the sidings do both left and right points, wouldn't I need 2 subs?

Easily, Modern signalling uses as few signals as possible and uses some form of route indicator where it is necessary to indicate to drivers which route is set. Even in semaphore days it was common for a single shunting signal to read over several routes. You might, if you wish, add a route indicator in the form of an illuminated letter, I should think S or U for Sidings and Up would be appropriate here, but I would not have thought this was necessary.

 

41 minutes ago, Kinighit said:

Looking at other depots there seems to be starter signals on all lanes, would that be employed here maybe?

The shed might be track circuited with motorised points, in which case you need to decide exactly what the controlled area is. Signalling it would become quite a major undertaking, as well as opening up quite a large can of worms as you need to work out what the overlaps should be for entering the shed, something I have quietly ignored assuming every train would be stopped before the road was set.

 

You have not got any provision for running round trains entering or leaving the sidings. Are these multiple units? If you aren't doing any running round, you don't need a signal in the up direction on the down line before the crossover, since this is only needed so that locos running round don't need a route set through the crossover.

[Kinighit]

Right, I think I now have the main lines done, as per your advice!

 

I've been looking up different TMD's for their ground signals and what I have done seems reasonable, but always open to advice.