Layout signalling questions

[Pillar]

Hi All,

 

I'm trying to develop a signalling strategy for my layout, the tack plan for which is shown below.

 

The layout is set in North East England and may be operated anywhere from the 1970s to 1990s. It is a fictional freight yard with adjacent small DMU passenger terminus (possibly a former through station on a truncated branch line). The main junction between the running line and the yard is off-scene to the left and not part of the layout. However, it is possible for light engines to re-join the running line near the station.

 

I'm a novice when it comes to signalling, and would be grateful for advice on the following points in particular:

 

1) My thinking is that Signal A (which would probably not be modeled) would control access to the station for trains in the DOWN direction. If a train is already occupying the station, any further train would be held at Signal A. However, if a loco needed to enter the yard at this time, how would such a move be signaled? Would this require a subsidiary signal?

 

2) Similarly, Signal B releases trains from the station in the UP direction. Could a subsidiary arm here possibly be used to release a loco from the yard onto the running line?

 

3) Am I right in thinking there would be no signalling required in the yards, and that the turnouts here would be controlled by hand rather than from the signal box?

 

4) My understanding of ground signals is limited. Is it likely that any would be required for the track layout shown?

 

5) How would the trap point be controlled and signaled? Would this be the responsibility of the yard or the signal box?

 

Any advice regarding the above, or the track plan in general would be much appreciated.

 

Cheers,

 

Liam

 

 

 

 

Edited April 13, 2020 by Pillar

[RailWest]

Short answers:-

 

1. yes

2. If B applies to Up train from the platform, then any subsidiary signal on it would apply to the same line, so no. Signal B might well be on the platform anyway if space between the converging tracks was tight. See also 5 below.

3. yes

4. one (or maybe two, one for each route ) off scene on the Up line in line with A for anything reversing into the yard or platform. See also 5 below.

5, Trap worked from signal-box by same lever as the point at the end of the platform. Ground-signal next to the trap for movements out of the yard onto the Up line.

[Flying Pig]

4,5 - you don't really need a separate trap point as the point between the yard and loco release provides the necessary trapping. 

 

You need a signal for movements from the loco release to the main line and a yellow disc, passed at danger for movements into the yard, would be sufficient.  However, this being the former NER, perhaps two miniature arms stacked on the same post, the upper one reading to the yard, the lower to the main line, would also be appropriate?

 

BTW, as the NER was not a great builder of single track branches, it looks as though your platform has been built on the former down trackbed after the line was truncated.  If this is the case, the signalbox should of course be set back with empty trackbed in front of it.

 

I think this could be a very atmospheric small layout.

[RailWest]

4 hours ago, Flying Pig said:

4,5 - you don't really need a separate trap point as the point between the yard and loco release provides the necessary trapping. 

 

 

You are right in what you say, but as the OP had drawn a trap-point specifically (and at least he had remembered the need, not everyone does :-) ) then I worked on that basis.

 

Also by the 1990s I feel that the simpler arrangement than two ex-NER stacked signals would be more likely and in keeping with the 'simplicity' ethos.

[Grovenor]

Quote

BTW, as the NER was not a great builder of single track branches, it looks as though your platform has been built on the former down trackbed after the line was truncated.  If this is the case, the signalbox should of course be set back with empty trackbed in front of it.

Seems an unlikely scenario, using an existing platform would be much more likely unless it is a new station. The Op did suggest a former through station.

I would question the need for a double track line as it looks as though only light engines can enter or leave the yard. Is there another yard access off scene at the left?

[ejstubbs]

1 hour ago, RailWest said:

You are right in what you say, but as the OP had drawn a trap-point specifically (and at least he had remembered the need, not everyone does :-) ) then I worked on that basis.

 

But as Flying Pig pointed out, you don't need a trap.  Proceeding on the basis that a trap is needed simply compounds the error, it doesn't justify anything.

 

The turnout from the "Headshunt/loco escape" would be worked from the same lever as the point at the end of the platform, as you say the trap should be.  Think of it that way and it becomes even more clear that a separate trap would be unnecessary duplication.

[Flying Pig]

4 hours ago, Grovenor said:

Seems an unlikely scenario, using an existing platform would be much more likely unless it is a new station. The Op did suggest a former through station.

I would question the need for a double track line as it looks as though only light engines can enter or leave the yard. Is there another yard access off scene at the left?

 

In real life, the line might well be singled as far as the junction at the other end of the yard, but having double track just offscene increases the flexibility of the model.  Cassettes or a traverser would achieve the same result, but may not be desirable for other reasons.

 

As far as the platform goes, I don't think minimal replacement facilities post-rationalisation, perhaps not quite in the same spot as the original station, are at all out of character for the period and the layout as drawn pretty much indicates a platform on the former down trackbed as I've suggested.  It's doubtful whether the remains of a former double track station (as done very successfully on Easington Lane) could be suggested convincingly in the very limited space available, so riffing on the themes of contraction and decay is in my view a beter approach here..  

[Pillar]

Thanks for all of your thoughts. I'm keen to try and develop a believable backstory for the layout and it’s interesting to read all the different ways this could be approached.

 

I've attached a revised version of the sketch below. The principal changes are:

 

- Trap point removed.

- Spacing between the running line and yard revised to allow a prototypical (I believe?) spacing of 10ft between the yard and the former 'UP' line.

- Intact double line up-stream of the overbridge now represented by a DMU traverser.

- Signalling altered.

 

To give a bit of background; I based the concept on the idea of a 'half marshalling yard' in the book 'Modelling the British Rail Era'. I only have circa 40cm x 2.2m of space available, so running long trains is out of the question. I hope therefore to hide the shortened length of my trains by having only the loco and first few wagons appear in the scenic section.

 

I’m intending the station to be former NER in run-down/cut back condition. The area formerly occupied by the ‘UP’ track and platform will have been built over with yard paraphernalia of some kind. The yard itself will be kept deliberately generic in terms of its traffic as there are various types of wagons I’d like to run.

 

I think the road overbridge presents an interesting conundrum given that the line was formerly double track. I’m intending to base it on a girder type construction with stone piers and two spans; one span being smaller than the other and possibly having been replaced at some point. I got this idea from the bridge which carries St James Road over the railway near Gateshead, south of the former Tyneside Central Freight Depot. However, given that one of my piers will occupy the former UP track bed, this means the bridge must have been built after the line was singled. Does anyone have any thoughts regarding a plausible timescale for this, and what it might mean for the type of architecture used?

 

Regarding the signalling, I’ve tried to modify the diagram based on the advice above. However, I still have a few things I’m unsure about:

 

i) If a shunt disc is added at Signal A, as shown, my understanding is that this would allow the main signal to be passed at danger, but only for movements into the yard. This would presumably involve interlocking with the turnout opposite the signal box?

 

ii) Related to point i), how would the driver of a loco know that the turnouts are correctly set for entering the yard? Colour light signals have feather indicators to show which route is selected, but I’m unsure how this workings with semaphores.

 

iii) Would Signal C be a shunt disc or a normal starter? If a light engine was leaving the yard intending to travel back up the running line, would this still be considered a ‘shunt’ movement? I’m hoping a shunt disc will be plausible for at least one of my signals as I do like the look of them.

 

Sorry this post is a bit long!

 

Cheers,

 

Liam

 

Edited April 17, 2020 by Pillar

[Flying Pig]

On 17/04/2020 at 18:28, Pillar said:

Regarding the signalling, I’ve tried to modify the diagram based on the advice above. However, I still have a few things I’m unsure about:

 

i), ii) the signals at A would be interlocked with the points and route knowledge would tell the driver which signal applied to which route.

 

iii) signal C should be moved to the right, beyond the toe of the points leading to the yard; these points can then act as a trap for the loco release, which is why a separate trap isn't needed.   

 

Precisely what form signals A and C would take depends on a number of factors:

 

- what was the original track layout?  The reversed connection from the yard throat seems rather odd - perhaps the loco release is the stub of a former branch with a junction by the box?

 

- how was the original layout signalled?

 

- what other signals are offscene?  

 

- how would BR(NE) or BR(E) (after 1967) have resignalled when the lines were truncated and singled - probably late 1960s/early 1970s?

 

Note that the date of singling also affects your bridge design. 

[Pillar]

It's been a while since I last posted regarding this project. Due to space constraints, and also to include a more complex turnout formation, I've tweaked the plan to use a 3 way turnout. This also opens up the possibility of adding a stabling siding or loco fuelling point on the former UP platform location.

 

I've also removed the junction between the yard and the running lines.

 

Does anyone have any thoughts on whether this arrangement seems reasonable; particularly the use of the 3 way turnout?

 

Cheers

 

Liam