Ground signals, is this overkill?

[Matti]

I'm not really sure even after tons of googling how ground signals should really be deployed. It seems largely open to interpretation depending on the siding/situation. So, I've got one example (see pics below) of a siding that comes off of my mainline, and I wondered if I could get your thoughts on whether what im thinking is total overkill.

 

Then, I also don't know, does double red mean don't go? or does double red mean, you can't go straight, so at the turnout you're turning off? (So to speak).

 

Then I've got some questions if I may?

1. Some parts of my layout, I just can't fit a ground signal on the left-hand side. Is it ok to place it on the right?
2. Should I mix between these new modern ground signals and BR Diesel ground signals? (I'm just modelling a modern-ish era) no specific time-frame in mind.
3. The BR diesel signals only have three lights; 1 red, 2 white. What does it mean when the 1x red and the 1x adjacent white lights are on?
4. Would ground signalling work for a three-way point in my depot area? or, for the main routes to the fiddle yard lines, should I use main signalling?
5. Could a signal be used outside of a shed, to signal DONT COME IN! haha?
6. What's more common in the modern era, the signal heads below or the 3-aspect ground signals?

 

I realise, these are a lot of questions, so I wanted to reference some places I'd google'd just so you don't think my first port of call was being lazy.

Wikipedia

Google Images

Network Rail

Hornby

(Don't ask why) Dorman's official technical data sheets for ground signals

Signal questions on RMweb

 

Big thank you in advance

[RailWest]

In simple terms....

 

1. There needs to be a trap point in the exit from the sidings onto the main line.

2. You would need one shunt signal reading into the sidings and one at the trap reading out.

 

That's all.

 

For a more comprehensive answer, it would be useful to know about (a) the signalling on the main line and (b) the layout of the sidings and what they are used for.

 

[Matti]

3 hours ago, RailWest said:

In simple terms....

 

1. There needs to be a trap point in the exit from the sidings onto the main line.

2. You would need one shunt signal reading into the sidings and one at the trap reading out.

 

That's all.

 

For a more comprehensive answer, it would be useful to know about (a) the signalling on the main line and (b) the layout of the sidings and what they are used for.

 

 

Thank you for the reply.

 

So some context;

 

The first siding to the left, the bottom half is a maintenance shed and the above half is a piece of track ending in a buffer. The aim is to store wagons / freight in. The second red line from the left, is a second siding where a loco can be stored along with freight also.

 

Mainline signalling: still TBC I'm working on that with my stations and wether lines are bi-direction or not.

 

With regard to the shunt signals, how comes you wouldn't necessarily out one over the two sidings to stop a train progressing over a point that's not set for the right direction/could cause a derail? Is it because the yard staff assume that they move things knowing the direction of points?

[RailWest]

The internal workings of a simple yard would not normally be the concern of a signalman, he would deal merely with controlling movements into or out of it.

 

Points within the yard would normally be worked by local hand-levers. In the trailing direction they would be pushed over by anything that passed over them when wrongly set. In the facing direction.....well, you simply, stop, reverse back, and b*****k the shunter for setting it wrong :-)

[Dave-5-5-7]

As previously mentioned,  the points within the yard wouldn't normally be worked by the signal box so would not be signalled by it. hand levers for the ground crew and hand signals would be the norm. Here is a section of my layout signal box diagram. 
It shows where the line from my depot works to the mainline, signal 37 protects the mainline. As you can see the lines within the depot do not show the actual layout of the depot nor any point numbers or signals. All the signalman at the signal box is interested in is things coming off and going onto the depot.  Coming onto the depot, each line that a train can be signalled from, into the depot, has a shunt signal.  So 942/944/946 are all main aspect signals (platform to down main) with position light shunt signals below them (for platforms to depot or platform to down siding), 38 is a ground position light mounted on the floor as all movements out are shunt moves. 

[Matti]

On 25/03/2020 at 22:39, Dave-5-5-7 said:

As previously mentioned,  the points within the yard wouldn't normally be worked by the signal box so would not be signalled by it. hand levers for the ground crew and hand signals would be the norm. Here is a section of my layout signal box diagram. 
It shows where the line from my depot works to the mainline, signal 37 protects the mainline. As you can see the lines within the depot do not show the actual layout of the depot nor any point numbers or signals. All the signalman at the signal box is interested in is things coming off and going onto the depot.  Coming onto the depot, each line that a train can be signalled from, into the depot, has a shunt signal.  So 942/944/946 are all main aspect signals (platform to down main) with position light shunt signals below them (for platforms to depot or platform to down siding), 38 is a ground position light mounted on the floor as all movements out are shunt moves. 

 

Hey,

Thank you for the detailed response and sharing of your track plans. What a great section of track, I love the complexity yet flexibility that trains can manouver all over the shop. Nice!

 

In your layout, what are 39, 37 and L.O.S signalling? On 942,944,946 - the shunt signals are currently depicted white - is that coincidence/just to help you plan? What colouring red or white, would they be if they were signalling a train into the depot?

 

and am I reading it right that 38 is signalling for 0308 and 0310. is 38 giving a train permission to exit the the pieces of track, technically onto he main-line to perform whatever operation needed?

[RailWest]

LOS = Limit Of Shunt, ie a permanent red 'stop' indication, designed to limit 'wrong direction' movements.

 

The 'white' shunts are subsidiary signals which show no indication when 'on', as then the driver obeys the indication of the main signal above it.

[ikcdab]

If it helps,  I have always been under the impression that clearing a ground disc is the sugnalman saying to the driver, "I've done my bit by working the point lever, now it's up to you".

Having said all of that,  on the west Somerset, at Blue Anchor, the starter for down trains from the up loop is a disc. Also, there is a running disc on the mainline for up trains. This is because the up home is too far from the loop points to provide any detection and the disc does that.

[RailWest]

2 minutes ago, ikcdab said:

If it helps,  I have always been under the impression that clearing a ground disc is the signalman saying to the driver, "I've done my bit by working the point lever, now it's up to you".

Having said all of that,  on the west Somerset, at Blue Anchor, the starter for down trains from the up loop is a disc. Also, there is a running disc on the mainline for up trains. This is because the up home is too far from the loop points to provide any detection and the disc does that.

Essentially so :-)

 

The clearance of a main signal indicates that the route is set and clear for the train to proceed to the next main stop signal. The clearance of a shunt signal is an indication that the route is set and the train may proceed as far as the next signal (which may be a main signal or another shunt signal) but the route is not necessarily clear, so effectively you have to 'drive on sight'.

 

[ As an aside, the old GWR 'backing signals' were even more restrictive, as they indicated merely that the route was set - the driver could not proceed without authorisation from the shunter. I always found this a curious distinction, given that IMHO the 'full size' nature of such a signal might imply that in fact it had more authority than a diminutive ground signal. ]

 

With regard to the current arrangements at BA, the 'running shunt' 12 in advance of the Up Home was provided when the line re-opened to cover the gap previously occupied by the siding point 8 and its own FPL locking bar 12. The disc on the Up loop is a relatively recent addition and is 'fixed' in the 'on' position, so movements have to be specifically hand-signalled past it (as I'm sure Ian knows anyway!).

[ikcdab]

1 minute ago, RailWest said:

Essentially so :-)

 

The clearance of a main signal indicates that the route is set and clear for the train to proceed to the next main stop signal. The clearance of a shunt signal is an indication that the route is set and the train may proceed as far as the next signal (which may be a main signal or another shunt signal) but the route is not necessarily clear, so effectively you have to 'drive on sight'.

 

[ As an aside, the old GWR 'backing signals' were even more restrictive, as they indicated merely that the route was set - the driver could not proceed without authorisation from the shunter. I always found this a curious distinction, given that IMHO the 'full size' nature of such a signal might imply that in fact it had more authority than a diminutive ground signal. ]

 

With regard to the current arrangements at BA, the 'running shunt' 12 in advance of the Up Home was provided when the line re-opened to cover the gap previously occupied by the siding point 8 and its own FPL locking bar 12. The disc on the Up loop is a relatively recent addition and is 'fixed' in the 'on' position, so movements have to be specifically hand-signalled past it (as I'm sure Ian knows anyway!).

Chris, I had forgotten about that the disc signal at BA was fixed at caution! 

Also there is a disc starting up trains from the down loop at Williton. Before the resignalling this was also the starter to crowcombe but I have forgotten how it worked. With the resignaling there is now a starter further out so is it still the section signal....i can't remember and I don't have the energy to check the paperwork this morning. Lockdown makes one very lazy.

[The Stationmaster]

1 hour ago, ikcdab said:

Chris, I had forgotten about that the disc signal at BA was fixed at caution! 

Also there is a disc starting up trains from the down loop at Williton. Before the resignalling this was also the starter to crowcombe but I have forgotten how it worked. With the resignaling there is now a starter further out so is it still the section signal....i can't remember and I don't have the energy to check the paperwork this morning. Lockdown makes one very lazy.

If it's a ground disc fixed at caution it must be unique in the annals of British signalling.  From Chris' description it sounds to me that it is fixed at danger - which is still pretty unusual for a ground disc (it really ought to be a STOP lamp) but if that's the way the WSR want to do it then so be it - but they lose the advantage of detection doing it that way.

[RailWest]

It is indeed fixed at danger.

 

AIUI the rationale was that there had been an increasing need to start movements back towards Minehead from the Up loop. Providing a working signal (of whatever form) would have required extensive re-locking of the 'stud' frame. The provision of a 'fixed' signal (and a ground signal was a lot easier to install than a full semaphore!) accompanied by the requisite green flag was considered to be at least better than a flag on its own.

[Dave-5-5-7]

8 hours ago, Matti said:

 

Hey,

Thank you for the detailed response and sharing of your track plans. What a great section of track, I love the complexity yet flexibility that trains can manouver all over the shop. Nice!

 

In your layout, what are 39, 37 and L.O.S signalling? On 942,944,946 - the shunt signals are currently depicted white - is that coincidence/just to help you plan? What colouring red or white, would they be if they were signalling a train into the depot?

 

and am I reading it right that 38 is signalling for 0308 and 0310. is 38 giving a train permission to exit the the pieces of track, technically onto he main-line to perform whatever operation needed?

you can effectively disregard the 03xx numbers. They're track circuits and whilst they help the signalman know where the train is, they mean little to a driver. 

942, 944 and 946 are platform signals. Main 3 aspect signals which show Red, Yellow or Green, in this design of panel, the signalman only sees if the signal is showing stop or proceed, not the full aspect. The white one below it is a position light, a bit like a ground position light (the official term for a colourlight shunt signal) but shows no red. When a move is cleared into either the depot or the down siding, it will show white with a red aspect indicating, as Railwest says, that the route is set, but the line may not be clear to the next signal. 

LOS is as mentioned, a Limit of Shunt Board. In modern terms it is a Ground position light fixed at danger. Older times would have seen an illuminated sign stating "Limit of Shunt" and it is as far as the train can go on that line when shunting on the Up.. On the down it doesn't need one as 940 signal protects the line. 
37 and 39 are shunt signals (ground position lights) but the box with the 4 in it indicates it has a route indicator to tell the driver where they are going. In my case it will show a 1, 2 or 3 for platforms 1,2 and 3 and an S for the siding. 38 is the GPL for shunting out of the siding to the up, down, siding or depot, it's likely to receive a route indicator showing U, M, S and D respectively. 942, 944 and 946 don't have a route indicator because the main aspects only signal to the Down Main. The Position lights should have one, but it's not easily done. 

 

 

[The Stationmaster]

37 minutes ago, RailWest said:

It is indeed fixed at danger.

 

AIUI the rationale was that there had been an increasing need to start movements back towards Minehead from the Up loop. Providing a working signal (of whatever form) would have required extensive re-locking of the 'stud' frame. The provision of a 'fixed' signal (and a ground signal was a lot easier to install than a full semaphore!) accompanied by the requisite green flag was considered to be at least better than a flag on its own.

A nice GWR pattern STOP board would have looked a lot better   (and be less easily missed by Drivers)

[RailWest]

1 minute ago, The Stationmaster said:

A nice GWR pattern STOP board would have looked a lot better   (and be less easily missed by Drivers)

I suppose the answer is that they did not have one, whereas they did have a spare ground signal - which incidentally I believe had seized up and therefore could not be worked anyway :-)

 

[ikcdab]

1 hour ago, The Stationmaster said:

A nice GWR pattern STOP board would have looked a lot better   (and be less easily missed by Drivers)

It's primarily used for santa specials which arrive and depart from the up platform. So from that point of view,  I'm not sure a stop board would be much use as the trains are sitting in the platform and are stopped anyway. 

Many years ago I donated/lent a ground disc to the museum at Blue Anchor which had come from Castle Cary. I seem to remember that either this whole signal or maybe bits of it were used for the new fixed disc. Maybe Chris can recall

[RailWest]

17 minutes ago, ikcdab said:

Many years ago I donated/lent a ground disc to the museum at Blue Anchor which had come from Castle Cary. I seem to remember that either this whole signal or maybe bits of it were used for the new fixed disc. Maybe Chris can recall

The short answer is that I do not know. The last time that I was able to look, there was still a ground signal in BARM, which may well have been yours? I was told that the one used in the six-foot had been in store at Crowcombe. 

 

[Matti]

14 hours ago, Dave-5-5-7 said:

you can effectively disregard the 03xx numbers. They're track circuits and whilst they help the signalman know where the train is, they mean little to a driver. 

942, 944 and 946 are platform signals. Main 3 aspect signals which show Red, Yellow or Green, in this design of panel, the signalman only sees if the signal is showing stop or proceed, not the full aspect. The white one below it is a position light, a bit like a ground position light (the official term for a colourlight shunt signal) but shows no red. When a move is cleared into either the depot or the down siding, it will show white with a red aspect indicating, as Railwest says, that the route is set, but the line may not be clear to the next signal. 

LOS is as mentioned, a Limit of Shunt Board. In modern terms it is a Ground position light fixed at danger. Older times would have seen an illuminated sign stating "Limit of Shunt" and it is as far as the train can go on that line when shunting on the Up.. On the down it doesn't need one as 940 signal protects the line. 
37 and 39 are shunt signals (ground position lights) but the box with the 4 in it indicates it has a route indicator to tell the driver where they are going. In my case it will show a 1, 2 or 3 for platforms 1,2 and 3 and an S for the siding. 38 is the GPL for shunting out of the siding to the up, down, siding or depot, it's likely to receive a route indicator showing U, M, S and D respectively. 942, 944 and 946 don't have a route indicator because the main aspects only signal to the Down Main. The Position lights should have one, but it's not easily done. 

 

 

 

Wow, blown away by the detail I love it! Thank you for the help. If I could pinch your knowledge for my layout that would be awesome haha!

 

The LOS makes a lot of sense now. So this is a ground signal, fixed at danger, that main-line trains will ignore, but a shunter must abide by and never pass (otherwise he/she risks going out onto a piece of track not suitable I'm guessing! That would explain if my understanding is right, the fixed ground signals often found on stations I've been too just outside the station (several hundred yards).

 

I think im going to incorporate the LOS thinking into my layout. it's super nice. 

 

Thank you again, going to take lots of learnings from your initial layout here! 

[Dave-5-5-7]

1 hour ago, Matti said:

 

Wow, blown away by the detail I love it! Thank you for the help. If I could pinch your knowledge for my layout that would be awesome haha!

 

The LOS makes a lot of sense now. So this is a ground signal, fixed at danger, that main-line trains will ignore, but a shunter must abide by and never pass (otherwise he/she risks going out onto a piece of track not suitable I'm guessing! That would explain if my understanding is right, the fixed ground signals often found on stations I've been too just outside the station (several hundred yards).

 

I think im going to incorporate the LOS thinking into my layout. it's super nice. 

 

Thank you again, going to take lots of learnings from your initial layout here! 

 

Sort of, the LOS is for trains shunting in the opposite direction to the normal flow of traffic. A main line train would only see the rear of it and so would ignore it.

It acts as a fixed stop signal, however it can be passed by a train with permission from the signalman. It is generally there to protect something, maybe trailing points. In my case, just off picture to the left is a level crossing, the LOS prevents a loco shunting a train from getting too close to the level crossing. 

[Titanius Anglesmith]

5 hours ago, Dave-5-5-7 said:

 

Sort of, the LOS is for trains shunting in the opposite direction to the normal flow of traffic. A main line train would only see the rear of it and so would ignore it.

 

I can think of at least three LOS boards on London Underground that face the normal running direction are are passed by hundreds* of trains a day

 

* probably less at the moment with the reduced levels of service

[bécasse]

47 minutes ago, Titanius Anglesmith said:

 

I can think of at least three LOS boards on London Underground that face the normal running direction are are passed by hundreds* of trains a day

 

* probably less at the moment with the reduced levels of service

But the signalling on the London Underground is very different to that on the main line railways, especially today of course, but historically too.

[Titanius Anglesmith]

2 hours ago, bécasse said:

But the signalling on the London Underground is very different to that on the main line railways, especially today of course, but historically too.

 

True, although there is a facing LOS board at Harrow On The Hill on the northbound main, used (exclusively, in normal running?) by the Chiltern trains out of Marylebone.  After I posted that I started looking through the scale plans out of curiosity.  I counted five facing LOS's on the Central Line and five more on the District before I gave up looking.

[Dave-5-5-7]

6 hours ago, Titanius Anglesmith said:

 

I can think of at least three LOS boards on London Underground that face the normal running direction are are passed by hundreds* of trains a day

 

* probably less at the moment with the reduced levels of service

I was referring to my signalling plan, not LUT or any other box. Where a signal is provided in the direction of travel, an LOS isn't generally needed such as here at Immingham West. 

[RailWest]

AFAIK in general the idea of a LoS board was to provide a 'signal' to terminate a wrong-direction movement in places where otherwise no working signal would have been required.

[Grovenor]

On 20/03/2020 at 00:18, Matti said:

Then, I also don't know, does double red mean don't go? or does double red mean, you can't go straight, so at the turnout you're turning off? (So to speak).[/quote]

Double red means, stop, which is the saame as don't go. You can go when it shows double white.

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Then I've got some questions if I may?

 

1. Some parts of my layout, I just can't fit a ground signal on the left-hand side. Is it ok to place it on the right?

 

 

Yes and the signal will be fitted with an arrow plate to point at the track it applies to.

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2. Should I mix between these new modern ground signals and BR Diesel ground signals? (I'm just modelling a modern-ish era) no specific time-frame in mind.

given you hsave so few they would most likely all be the same type.

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3. The BR diesel signals only have three lights; 1 red, 2 white. What does it mean when the 1x red and the 1x adjacent white lights are on?

Same as the double red, they are just an older design (pre-LED lamps).

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4. Would ground signalling work for a three-way point in my depot area? or, for the main routes to the fiddle yard lines, should I use main signalling?

Depot areas are not usually signalled, would just have hand point levers.

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5. Could a signal be used outside of a shed, to signal DONT COME IN! haha?

For this sort of purpose it is not usual to use signals, some alternative design if light indicators is more likely.

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6. What's more common in the modern era, the signal heads below or the 3-aspect ground signals?

Since the use of LED lamps allowed a change to double red for stop the original 3 light versions are produced with the bottom right lamp able to show red or white thus giving double red or double white from the 3 lenses, whether the 4 light or 3 light versions are more common I don't know.

 

Edited March 30, 2020 by Grovenor