Signalling advice

[jimbobbloor]

Hi,

 

I'm in the early stages of building my layout and I need some help with signalling. I've tried to read up on the topic but without much success.

 

Details of the layout:

• Set in present day
• Mainline station with a branch line used mainly for mostly freight 
• Small depot next to the station
• N Gauge

 

On the track plan, I've marked where I think the signals should go but I don't know if the position is correct or what type of signal should be at each location (2 aspects, 3 aspects, ground etc).

 

I'd be really grateful if someone with better knowledge on this topic could assist me. 

 

Thanks in advance.

 

Edited March 14, 2019 by jimbobbloor

[Joseph_Pestell]

There are few definite rules about signalling. Whether they are two-aspect, three-aspect or four-aspect depends mainly on the frequency of trains on the route.

 

I am not convinced that signal 7 is needed at all. 9 looks even less likely unless it is a ground signal for shunting.

 

If at all possible, access to the TMD should be re-arranged so that it leads to the branch platform (via a headshunt).

 

Signals 1, 4 & 8 need to be able to indicate which route is set for the train. That might be by feathers, more than one signal head (old-fashioned) or by theatre indicator.

 

13 would probably be a ground signal and there should also be ground signals for shunting moves opposite 1 & 8.

[PaulRhB]

Bit difficult on the phone but here’s my suggestion. I’ve cut out two signals, 7 & 9, as unless it’s a long enough distance to hold a train they are unnecessary. 

I’ve changed some to Ground signals, 2 red 2 white for shunts and the sidings exit, I’ve assumed that the shunter controls the point in blue and movements inside the mpd. 

I’ve added two Calling on signals beneath the main aspects, 3 & 12, to control moves into the sidings. They show 2 white with the main aspect still red to authorise a move into the siding. 

Feathers are annotated on the diagram. 

 

Edited March 13, 2019 by PaulRhB

[phil-b259]

2 hours ago, jimbobbloor said:

....... but I don't know if the position is correct or what type of signal should be at each location (2 aspects, 3 aspects, ground etc).

 

I'd be really grateful if someone with better knowledge on this topic could assist me. 

 

 

 

 

Firstly, I must emphasise that signalling is installed to meet the demands of the service - not the other way round! Thus when attempting to signal ANY layout - bet it in model form or out in the real world is to have a clear idea of exactly what movements are going to be made. You then place signals on the basis of said movements (taking into account things such as train lengths and linespeed). You have made a decent stab at this so far - but more attention to potential operations will allow you to make further refinements. While I could offer a solution - you will benefit greatly from devising your own solution rather than it simply being served up on a plate as it were

 

Secondly, when it comes to types of signals there are some fairly basic rules which will help you in selecting the type of signals required.

 

One of the most significant is that a driver must NEVER* encounter a red colour light signal without having first passed a yellow cautionary aspect with enough distance to brake to a stand from full linespeed without using the 'emergency' setting

 

Signal 1 thus CANNOT be a 2 aspect for example - it HAS to be a 3 or 4 aspect one so as to be able to show a yellow when signal 4 is at red .

 

On the other hand signals 11 and 12 could theoretically be 2 aspect ones as the preceding signal (no. 8 as no. 9 is not needed) could be a 3 aspect and give the required cautionary warning.

 

However given the presence of multiple platforms, a branch line and a TMD its likely that 2 aspect signalling would insufficient to accommodate the traffic levels on the main line so you would more realistically looking at a 3 aspect job throughout.

 

Also you should note the key difference between a 'main' signal (be it a 2, 3 or 4 aspect job) and a ground / position light / shunt signal (they all look pretty much the same despite being described differently). Understanding this will enable you to identify where each type is required to be placed (they can of course be combined if both are needed in the same location)

 

When a 'main' signal shows a proceed aspect (i.e. Y, YY or G) it GUARANTEES to the driver that there are NO TRAINS in the upcoming signal section(s)

 

When a ground / shunt / position light / call on shows a proceed aspect it proves nothing about the status of the section of line ahead - there may be wagons, another locomotive / unit, berthed coaching stock etc present and as such any movements MUST be made cautiously with drivers able to stop their train / loco within the distance they can see to be clear.

 

You CANNOT use a 'main' aspect for shunt movements or to authorise a train to enter a piece of track which is already occupied - and equally it is undesirable to use ground / shunt / position light signals for ordinary train movements as they have to proceed cautiously due to the 'stop within the distance you can see to be clear rule'.

 

Remember when I said it is essential to understand the operations - the two statements above are why it is so crucial to have this in place at the start...

 

 

* Some very low speed lines - typically the exit from freight spurs may well skip the requirement for a 'yellow before red' rule - but this is very much the exception to the rule and not something you should consider for your layout.

[PaulRhB]

I agree with Phil, probably at least 3 aspect signalling although the branch starter might be a 2 aspect as a Section signal for the single line. 

On a slightly pedantic note I t is possible to use a main aspect for shunt moves as you can shunt out from the station using the main aspect onto the mainline but as Phil notes it has to be a ground signal or Calling On to bring a train into an occupied platform or a siding as it tells the driver to proceed at caution and be ready to stop at the train / obstruction. 

[iands]

I would also suggest that signal 10 is currently shown in an impracticable position. It needs to be moved closer to the points it is protecting, otherwise the siding is effectively unusable. I echo phil-b259s comment that you have made a pretty decent stab at signalling your proposed layout so far.

[RailWest]

In the dead-end spur at bottom left, then I would suggest there needs to a trap-point immediately to the right of signal 13, facing to moves OUT of the spur, to protect the platform road.

 

Assuming that siding at the extreme bottom middle is NOT a passenger-only platform line, then there needs to a trap-point immediately to the right of (relocated) signal 10, facing to moves OUT of the siding, to protect the main line.

 

Not all the possible moves back across the crossovers at either end appear to be signalled from all the platform roads.

[Dave-5-5-7]

13 hours ago, PaulRhB said:

Bit difficult on the phone but here’s my suggestion. I’ve cut out two signals, 7 & 9, as unless it’s a long enough distance to hold a train they are unnecessary. 

I’ve changed some to Ground signals, 2 red 2 white for shunts and the sidings exit, I’ve assumed that the shunter controls the point in blue and movements inside the mpd. 

I’ve added two Calling on signals beneath the main aspects, 3 & 12, to control moves into the sidings. They show 2 white with the main aspect still red to authorise a move into the siding. 

Feathers are annotated on the diagram. 

 

Just to add something, feathers are only required for diverging routes, the main route wouldn't have them. So signal 1 would be main indication, no feather to the main platform, say the one with signal 4 at the end, to go to platform with signal 5 on it, signal 1 would show a yellow or green aspect (yellow if 5 is red, green if 5 is yellow or green) plus a feather indication. 
Same would apply to 8, main head aspect to signal 11, then either of 2 feathers for 12 and bay. 
Incidentally as Paul has put a ground signal for the upper black line to return to the station, you'd need another signal along the track to prevent the need to shunt into forward section. 

 

 

[Dave-5-5-7]

I've attached the signal box diagram for my under instruction layout. This is about the 5th draft and there are further alterations. A couple of things I'll point out. On most panels with colourlights, only red and green are shown. To a signalman the signal is either on (caution/danger) or off (proceed), whether that off is yellow, two yellows or green doesn't matter. I mention this just so people know that because the diagram shows 2 aspect signals, they aren't two aspect in the flesh. 
Diverging routes are shown with feathers, or in some cases like 979 and 974 with theatre indicators. These are sometimes used in place of feather when they could be come confusing. Technically a colour light signal can have up to 6 feathers. 3 on each side + the main indication so 7 routes in total. Some signals also have sub signals mounted on the post like 983 to allow for shunt moves into occupied platforms. 

When it comes to model signalling, it can be as indepth or as basic as you want it to be. As you can probably tell, signalling is a huge part of the experience for me, so that bit has to be as close to bang on with a few compromises. This is going to be a fully working N-X panel. 

 

[Dave-5-5-7]

Me again, as I've been up all night (have a 3 year old with chicken pox and I'm recovering from surgery so both of our sleep patterns are buggered) I threw this together. 
Couple of notes, Signals 101, 114 and 118 show their red aspect greyed out. This is because they would be your distant signals if you are a stand alone signalbox they wouldn't have a red aspect, or if you work to other boxes a couple of miles away then those boxes would clear red to yellow, you'd clear yellow to green. The reverse happens with 104, 107, 113, you control red to yellow, the next box controls yellow to green, if there is no next box then they'd be 2 aspect red/greens. 
116 has two feathers, the horizontal one takes you into the bay (I wasn't sure if it's a platform or not so drew it as one) and the diagonal feather takes you into "platform 4". 
Note I swapped 112 and 114 points over, prototypically it was always designed so there were as few facing points in the main line as possible. As the main platform route based on your (very good if I may say) plan of the station, the bay should feed from the lower platform. It's nothing major so if you've laid the track don't loose any sleep over it. 
A ground signal 64 is provided to the right of 116 crossover. This would be the best place for loco moves as every line is accessible from this point. 
60 ground signal is provided to the left of the plan before 1004 crossover, same reason as above. 
102 signal, exit from depot could be a ground signal or a full height colourlight, either would work. 
103 should have no feather and a post mounted sub signal to access the yard but I don't think they're available in model form (I could be wrong) so it could be approach release. As you're entering a yard the circuitry would hold the signal at red until the loco was almost at a stand at it, it would then clear to yellow + feather. 

Anyway hope you don't think I've stomped all over your layout, signalling is a big interest of mine so I try and help where I can. 

*Edit* I did forget to mention, not every signal has to be physical. On my layout plans on the post above, signals P637/638 977/984/971/974/992/987 and 987R are all "off scene" so are only there for reference. 

 

Edited March 14, 2019 by Dave-5-5-7

[PaulRhB]

Yes quite right on the feathers, I was thinking routes and copied it!

I do think your main aspect 102 Signal onto the Up Main is unlikely though Dave unless that line is fully reversible and there’s a crossover off the left side. More likely a ground signal with a limit of shunt board around the distant 101. 

60 & 64 ideally need to be on the left side of the track

103 & 116 will need calling on subsidiary signals if trains need to attach. 

110 would also need a subsidiary for moves to the MPD limit of shunt. 

108 needs one too to enter the siding. 

 

This is where signalling really confuses people because while the principles are really simple, thinking of all the possibilities catches you out as we’re proving tuning this between us  

 

It happens in the real world too which is why it goes through several people and hopefully us mortals in the Ops dept to make sure it’s flexible enough for current and future moves. We get calls as new flows and timetables are created to check what the Signalling allows physically and timings. 

 

 

 

[Joseph_Pestell]

14 minutes ago, PaulRhB said:

 

I do think your main aspect 102 Signal onto the Up Main is unlikely though Dave unless that line is fully reversible and there’s a crossover off the left side. More likely a ground signal with a limit of shunt board around the distant 101. 

 

 

 

 

Paul, it's an unlikely signal because it's an unlikely arrangement of track (facing rather than trailing connection). This happens quite often on RMWeb when we are asked for signalling advice.

 

Likewise, Dave has done well to draw the whole signalling system rather than just the ones that will be visible on the layout. Without a wider context, it's hard to get it "right".

Edited March 14, 2019 by Joseph_Pestell
Clarity

[Dave-5-5-7]

8 minutes ago, PaulRhB said:

Yes quite right on the feathers, I was thinking routes and copied it!

I do think your main aspect 102 Signal onto the Up Main is unlikely though Dave unless that line is fully reversible and there’s a crossover off the left side. More likely a ground signal with a limit of shunt board around the distant 101. 

60 & 64 ideally need to be on the left side of the track

103 & 116 will need calling on subsidiary signals if trains need to attach. 

110 would also need a subsidiary for moves to the MPD limit of shunt. 

108 needs one too to enter the siding. 

 

This is where signalling really confuses people because while the principles are really simple, thinking of all the possibilities catches you out as we’re proving tuning this between us  

 

It happens in the real world too which is why it goes through several people and hopefully us mortals in the Ops dept to make sure it’s flexible enough for current and future moves. We get calls as new flows and timetables are created to check what the Signalling allows physically and timings. 

 

 

 

I'd noticed 102, but I wasn't going to edit the post for the 6th time ha ha. 
Ground signals can be anywhere, there is typically an arrow indicating the line if there is any doubt. I deliberately left post mounted subs off the diagram. I don't know the availability and didn't want to cause confusion. I'm already building some in 4mm for my railway as I can't find anything suitable. To be honest most of the station starters would probably need subs in the prototype. 
As a signalling manager friend of mine says you will always find a prototypical situation for almost every scenario, and then you get those who think they know better. I remember at an exhibition trying to explain about signal sighting and why it wasn't wrong that the up home signal was the wrong side of the down line. I gave up eventually. 

 

[Joseph_Pestell]

1 minute ago, Dave-5-5-7 said:

I remember at an exhibition trying to explain about signal sighting and why it wasn't wrong that the up home signal was the wrong side of the down line. I gave up eventually. 

 

 

Are there any examples of colourlight signals mounted on the "wrong" side of the track these days. I thought that sighting problems are always addressed these days with a repeater.

 

Quite another matter, of course, for mechanical signalling. On the GWR and Midland, "wrong" side signalling was almost the norm because of the use of RHD locomotives.

[Dave-5-5-7]

revised with depot alteration. Note I'm using diagrams based on the 1960s style BR(E) panels, other types and styles are available. 

 

[PaulRhB]

I agree they can go either side but there’s usually plenty of space on our models and it avoids it constantly being pointed out, especially if we’ve designed it for him

I’ve used normal Eckon/Berko  ground signals for subs with just a white led so they are easier than a full one really.  

I’m not sure what you had in mind but I can’t see a use for subs on the other starting signals though unless they control entrance to a siding / limit of shunt board. 

Edited March 14, 2019 by PaulRhB

[Dave-5-5-7]

2 minutes ago, Joseph_Pestell said:

 

Are there any examples of colourlight signals mounted on the "wrong" side of the track these days. I thought that sighting problems are always addressed these days with a repeater.

 

Quite another matter, of course, for mechanical signalling. On the GWR and Midland, "wrong" side signalling was almost the norm because of the use of RHD locomotives.

the signal in question was mechanical, model was of Gainsborough Central. Colourlights tend to be repeated with a banner before the curve. 

[PaulRhB]

Modern installations have pretty much eliminated such practices due to ‘read through’ errors caused by it especially with GPS as they fit just about anywhere and sighting isn’t usually a problem when you are proceeding under caution or changing ends.  

[Joseph_Pestell]

16 minutes ago, Dave-5-5-7 said:

revised with depot alteration. Note I'm using diagrams based on the 1960s style BR(E) panels, other types and styles are available. 

 

 

Surely 101 needs a red aspect if a loco can be at that limit of shunt???

[Dave-5-5-7]

25 minutes ago, Joseph_Pestell said:

 

Surely 101 needs a red aspect if a loco can be at that limit of shunt???

Yes, thought I'd changed that. Try this, I made the new distant an auto repeater. Saves renumbering. 

 

Edited March 14, 2019 by Dave-5-5-7

[Dave-5-5-7]

42 minutes ago, PaulRhB said:

I agree they can go either side but there’s usually plenty of space on our models and it avoids it constantly being pointed out, especially if we’ve designed it for him

I’ve used normal Eckon/Berko  ground signals for subs with just a white led so they are easier than a full one really.  

I’m not sure what you had in mind but I can’t see a use for subs on the other starting signals though unless they control entrance to a siding / limit of shunt board. 

From my archive of box visits. The dead fuelling road, 99 on the right, 98 on the left. 
They seemed to go on a bit of an odd one recently, almost if a shunt move might every be made then a sub should be provided. There are a couple of signals around here with seemingly pointless subs on them. 

 

[PaulRhB]

That looks the same vintage as Salisbury  but we’ve had new metal buttons as they were breaking off!

Yes sometimes they add stuff like confetti, feathers are the latest craze as they want them for every route. When we did some signal sighting for a proposed main aspect on platform 1 we had to say it was confusing to have two feathers, when the other signals alongside didn’t, to get a traditional single feather just for the diverging route. 

[DavidBird]

19 hours ago, jimbobbloor said:

 

Back to the original diagram, I'd add this.  It appears that signals 11 and 12 are half way along the platform.  This is perfectly acceptable, as they are protecting the crossover.  The point to remember about signals, especially at stations, is that they are to show the state of the track section ahead and have nothing to do with the need for a scheduled station stop.

A train can only use the full length of either of these platforms if the exit points are correctly set and any previous train has cleared the overlap of the next signal.  Both platforms cannot be used at the same time, unless at least one is a short train.

What you've drawn in certainly not wrong, and I accept that it may be just the way you've drawn the diagram, but as I've interpreted it, it does slightly limit the flexibility of operations.

But having said that, I always think of a model layout "prototype inefficiency = modelling interest" and it may be an interesting scheduling  exercise to ensure that only DMUs use the Down Loop when the Down Main is used by an express.

Hope that helps.

Edited March 14, 2019 by DavidBird
Changed "U" &"D" to fit with Dave557's diagram.

[DavidBird]

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

...
103 should have no feather and a post mounted sub signal to access the yard but I don't think they're available in model form (I could be wrong) so it could be approach release. As you're entering a yard the circuitry would hold the signal at red until the loco was almost at a stand at it, it would then clear to yellow + feather. 

...

 

 

Just spotted this.  I think that 103 should have a feather, but for the split between P1 for the branch or P2 for the UM, and then a sub for the depot.

A non-working version can be made from Knightwing kits, but how easy it is to actually make both signals work I'm not sure.  Would a working 3a+feather with a dummy sub be acceptable, combined from the Eckon  and Knightwing models? Or would it be possible to adapt a ground signal to be mounted on a post?

[St. Simon]

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

Yes, thought I'd changed that. Try this, I made the new distant an auto repeater. Saves renumbering. 

 

 

Hi,

 

A very good diagram, it looks great. Looking at it most of it is right, but here are my comments, some have already been picked up (going by Modern Standards, the above diagram is excellent for historic pratice):

 

1. 60 should have an MI for going up to the Limit of Shunt
2. 103 should have a Position Light for moves into the TMD or a Position 2 JI with a Stop Board within the TMD.
3. 105 should be a Position 4 JI rather than a Position 1
4. If the Branch is mostly freight, it could be simple 2 aspect signalling for 107.
5. 108 should have a PL for going into the Headshunt
6. 110 should have a PL + MI for going up to the LOS on the Up Main
7. 116 Should have a SI if going into the Bay not a JI (although it is right for historic practices

 

I did start drawing up a signalling plan last night, but haven't finished, I'll try to finish it tonight.

 

Simon

Edited March 14, 2019 by St. Simon