Signalling Diagram for Sevenhampton

[Rods_of_Revolution]

Hi all,

 

I'm creating a small working diorama of a GW terminus and (after inspiration here) I thought a signalling diagram in the old GWR style would be nice to display with it. Anyway, not being a signalling expert, I thought I'd get those who are to cast their eyes over it. Is the signalling correct? Are the lever numbers in the right order? Does the diagram look approximately right?

 

 

Any opinions?

 

Thanks,

 

Jack

[TheSignalEngineer]

Firstly a few questions.

• What date is it supposed to be? That could make a big difference.
• What type of trains are intended? 
• How are you going to get wagons into the siding without a run-round loop?

If only one train is present on the branch at a time it may have no signalling other than the fixed distant plus a ground frame released by the token to allow access to the sidings, but you will still need somewhere to run round. 

[Rods_of_Revolution]

The track plan is deliberately basic, as it's effectively a small Inglenook diorama. The station is at the end of a fictitious branchline which leaves the Highworth branch (Swindon - Highworth) at Hannington. The era would be anything from the late 40s to early 60s (so it should be a newer diagram, but I like the pre-30s one.) Freight would be propelled the short distance from Hannington, guards van leading, with the guards van left in the platform and the train shunted into the sidings, returning to Hannington locomotive leading.  The passenger service would be a DMU, or single coach in a mixed train which would be left in the platform with the brake van. Originally the line would have continued further, but it was cut back to Sevenhampton as there was a factory there which relied on the railway to bring the workers to and from Swindon, by the time it was cut back DMUs were being used so they didn't include a loop and settled with propelling the freight.

The purpose of the diagram is to give added interest to the display of the diorama, so it'll have been signalled as if money was no object, where as in reality it would be a ground frame as you suggest, but that doesn't make for a very interesting display.

 

Thanks,

 

Jack

[Harlequin]

10 hours ago, Rods_of_Revolution said:

Hi all,

 

I'm creating a small working diorama of a GW terminus and (after inspiration here) I thought a signalling diagram in the old GWR style would be nice to display with it. Anyway, not being a signalling expert, I thought I'd get those who are to cast their eyes over it. Is the signalling correct? Are the lever numbers in the right order? Does the diagram look approximately right?

 

 

Any opinions?

 

Thanks,

 

Jack

 

Hi Jack, It looks nice!

 

The text on the original SBDs was stencilled and I don't think we know exactly what that stencil was before the 50's.

 

I used a free Google font called Lato, which looks close but there might be something better yet. I applied lots of tracking to space the characters apart and Small Caps to liven the text up.

 

The brown colour used for platforms, building edges and goods lines was a Winsor and Newton watercolour called "Fawn Brown". It's not clear what that looked like originally and there isn't an obvious modern equivalent. The only variation in the brown colour was the amount of dilution and so your goods shed colour should be related to the platform colour, and probably just a contour inside a pencil rectangle rather than solid.

 

The crossover points would probably be on the same lever.

 

Edited March 5, 2020 by Harlequin

[Guy Rixon]

I suspect that such a short line would have been worked "one engine in steam", so no signals needed at the time of the model.

 

The original signalling would suit the through station before the branch was truncated. Since there's no loop, it's not a block post and existed in the middle of a section, protected by possession of a staff or tablet. Therefore, again, no signals and the sidings would be worked by a ground frame unlocked by a key on the staff.

 

If BR resignalled it as a terminus, then you need to think what two-train movements are enabled by the signalling.

 

As drawn, a goods train might arrive while a passenger train is held in the platform, but it would be outside the home signal, so outside station limits and in the section. Therefore, that train has to shunt and go back to the junction before the passenger train can depart. Further, no passenger train may arrive while a goods train is present, because the section is occupied. My view, as a non-expert in signalling, is that you'd need another home signal, outside the sidings, to govern goods trains to the junction and probably you need a home signal for trains arriving at the station. Both these are likely to be some distance away (on the same post?), probably outside the layout.

 

A fixed distant 180 yards from the box seems too close, unless the the line speed is unusually low.

[The Stationmaster]

Really it doesn't merit any signals beyond a Fixed Distant (btw it is drawn with the arm on the wrong side of the post).  There would be usually be in reality - the very most - a two lever ground frame to work the crossover to the yard and the FPL on it.

 

But let's begin at the beginning.  If the line is to be worked as a twig off a branch it is going to be One Engine In Steam (OES) and there is no point at all in having a signal box as it would be impossible for more than one train to be there at any one time.  Now some GWR OES branches did have signal boxes (according to the nameplate on the front of them but in at least one case (Wallingford) the so called 'signal box' didn't even have a block telegraph which implies the GWR S&T Dept was maybe a little loose in the use of terminology.  

 

If you work on a similar loose interpretation of the words 'signal box' you have a justification for having one but with that track layout and the inevitable OES working you can forget ever seeing two trains there at the same time and you can forget the signals you have drawn - all there would be is a Home Signal at the toe of the facing point and a starting signal from the station platform, no ground discs - they're unnecessary in that situation and handsignals would be more than adequate for shunting the siding.  Even if you decide to keep the ground discs the one you have numbered 3 would in the greatest likelihood not be there anyway although 5 might survive.

 

You could readily have a signal box structure from a former through line reduced to a ground frame with all signals taken away - the GWR definitely did that sort of thing.  So you have a range of choices but at present you have fallen between some of them.  If you want to keep a signal box structure and keep some signals all you need,  the off scene Fixed Distant apart, is a Home Signal at the toe of the crossover, a starting signal from the platform line, and possibly a ground disc from the sidings.  Your lever frame would have the following levers -

1. Home Signal,

2. FPL,

3. Crossover to sidings,

4. Ground disc from sidings (If one is provided), and

5. Starting Signal from platform line.

No spares or spaces.

 

Now let's bring it forward to the age of the DMU (but see my later comment about that) - definitely by then nothing more than a two lever open air ground frame to work the siding connection - no signals at all.  But don't forget that - as far as I know - DMUs never worked the final remaining passenger services (which were only Workmen's trains) on the Highworth branch - they were loco worked right up to the end, using 204hp diesel shunters once steam working had finished.

 

 

[Happy Hippo]

If you reverse the crossover, you can have the semblance of a loop, which would greatly increase your operational capacity.

 

 

Without wishing to hijack your thread, this is what I have come up with for a layout I'm currently building.

 

No signalling is shown, but it has been discussed and agreed with The Stationmaster.

 

 

Yes it looks big, but it is 7 mm scale.

 

HTH

 

 

Edit:  By removing the passenger hutch, which allows for an autotrain or single car DMU to use the halt as a through platform, y you would get a terminal facility

Edited March 5, 2020 by Happy Hippo

[Rods_of_Revolution]

Thanks for all the input chaps!

 

I'll add a home signal. Would that allow trains to arrive on both tracks, or would that require a shunt signal on the home? Would there be a limit of shunt board?

 

Mike, you're right DMUs were not used on the Highworth branch, but I'm using modeller's license and bringing in a few elements from other Bristol Division branches, DMUs from Calne and the Signal Box/GF from Malmesbury. I hadn't noticed the distant arm being wrong, that was me cheating and mirroring rather than rotating it the software.

 

Thanks for the details on the drawing Phil, very useful; It was you who gave me the inspiration to have a go in the first place!

 

Richard, reversing the crossover would reduce the headshunt length, which needs to be a loco+2, to give a 3-2-2 Inglenook. The diorama is in N scale and it's tiny! It's a way to display my 50s/60s stock on society/demo stands, with the potential for operation to keep anyone on the stand with it entertained!

 

Cheers,

 

Jack

[bécasse]

1 hour ago, The Stationmaster said:

 

 

Now let's bring it forward to the age of the DMU (but see my later comment about that) - definitely by then nothing more than a two lever open air ground frame to work the siding connection - no signals at all.  But don't forget that - as far as I know - DMUs never worked the final remaining passenger services (which were only Workmen's trains) on the Highworth branch - they were loco worked right up to the end, using 204hp diesel shunters once steam working had finished.

 

 

IIRC all the Western's dmus were out of gauge for the Highworth branch. Even on hauled trains only specially modified and appropriately branded passenger rolling stock was permitted.

[Rods_of_Revolution]

1 hour ago, bécasse said:

IIRC all the Western's dmus were out of gauge for the Highworth branch. Even on hauled trains only specially modified and appropriately branded passenger rolling stock was permitted.

 

The B-Set used had the position of the roof vents altered to reduce the overall height, that said there were railtours using DMUs on the Highworth branch in the later days, so at least some DMUs were within the required loading gauge.

 

Cheers,

 

Jack

[Rods_of_Revolution]

Here's the updated plan:

[The Stationmaster]

4 hours ago, Rods_of_Revolution said:

Thanks for all the input chaps!

 

I'll add a home signal. Would that allow trains to arrive on both tracks, or would that require a shunt signal on the home? Would there be a limit of shunt board?

 

Mike, you're right DMUs were not used on the Highworth branch, but I'm using modeller's license and bringing in a few elements from other Bristol Division branches, DMUs from Calne and the Signal Box/GF from Malmesbury. I hadn't noticed the distant arm being wrong, that was me cheating and mirroring rather than rotating it the software.

 

Thanks for the details on the drawing Phil, very useful; It was you who gave me the inspiration to have a go in the first place!

 

Richard, reversing the crossover would reduce the headshunt length, which needs to be a loco+2, to give a 3-2-2 Inglenook. The diorama is in N scale and it's tiny! It's a way to display my 50s/60s stock on society/demo stands, with the potential for operation to keep anyone on the stand with it entertained!

 

Cheers,

 

Jack

Trains can only arrive on the main (i.e. platform) line.  However as the crossover to the yard is on that line the train would simply come to a stand at the Home Signal then the points would be set for it to go into the sidings - movement controlled by a handsignal.  Incidentally the GWR don't seem to have used the term headshunt preferring the word 'spur' however I don't think they would actually apply it on a 'box diagram unless there was a particular reason for it - and there's no reason for it in this case.   The branch itself would be used as the headshunt because it gives far more headroom to shunt and you can use the platform line to help with any sorting of traffic - plus that is where the brakevan would be shoved to get it out of the way.

 

Limit of Shunt boards are a total illogicality on single lines   (you can't have an LoS board in a situation where trains running in the normal direction approach them as a facing move).

[DCB]

I don't think the board of trade would never have allowed the branch to open if this was a terminus. 

No run round, 

 As a through station it looks ok,  and also as a through station on a truncated branch used as a long siding and special regulations allowing goods trains to be propelled to the terminus. Obviously all the signals would be out of use in this scenario.

 

Around the turn of the century years the GWR standardised on a four turnout station for single track branches , loop plus two sidings.

 

There was a plan for a line through Sevenhampton (Glos) it would have run from Andoversford to Winchcombe to Ashchurch and been instead of the Cheltenham - Honeybourne GWR line and been a MSWJR / Midland line, probably double track.  Sevenhampton would have been on quite a steep climb over the spur of the cotswolds between Abdoverford and Winchcombe probably not as steep as Andoversford to Notgrove through Salperton, 1 in 40 but probably the  MSWJR ruling grade of 1 in 75.  It would make quite a nice model.

[Titanius Anglesmith]

1 hour ago, The Stationmaster said:

 (you can't have an LoS board in a situation where trains running in the normal direction approach them as a facing move).

 

I was thinking about this recently.... there’s at least two LOS boards I can think of on LU that are approached in the facing direction on the main running line. Admittedly we sometimes do things a little differently on LU.... 

[Rods_of_Revolution]

2 hours ago, The Stationmaster said:

Limit of Shunt boards are a total illogicality on single lines   (you can't have an LoS board in a situation where trains running in the normal direction approach them as a facing move).

 

So the LoS exists to allow a route to be set from an Up direction signal onto a Down direction line (or vice versa), without the requirement to fully signal the route as bi-directional?

 

Thanks,

 

Jack

[RailWest]

A LoS board exists to limit wrong direction movements at locations where otherwise there would have been no fixed signal.  To all intents and purposes it is a signal with a permanent 'stop' aspect, so it can not be passed without specific authority from the signalman every time. A (bi-directional) single-line is traversed by running movements in both up and down directions, so by definition there can be no such thing as a 'wrong direction' move, hence the illogicality of a LoS in such cases.

 

On the other hand, it is quite feasible - and examples did exist - that at a passing-loop on a single line you could have a LoS at the entrance end of a loop, facing to movements coming back the wrong way from a shunt signal (eg the exit from a facing siding connection) at the far end of the loop, so as to stop any such movement  going back onto the actual single-line. See for example (admittedly not GWR) on the Down loop at Budleigh Salterton https://www.s-r-s.org.uk/html/srq/S3490.htm .

[Ken.W]

The term 'limit of shunt' can perhaps be a little miss-leading to the uninitiated.

It should be thought of more in terms of actually being a fixed STOP signal, or perhaps as it's modern equivalent of a position light signal with only red lights.

As RailWest said, it can only be passed on verbal authority of the signaller, and it's classed as a signal for doing so (and yes, it would count as a SPAD), so can not be used in situations where movements would normally be required to pass it.

[bécasse]

Of course, just to confuse the issue, the LBSCR had workable limit of shunt signs, effectively identical to their normal revolving dollies but with the letter L on their face. 

[The Stationmaster]

18 hours ago, Rods_of_Revolution said:

 

So the LoS exists to allow a route to be set from an Up direction signal onto a Down direction line (or vice versa), without the requirement to fully signal the route as bi-directional?

 

Thanks,

 

Jack

Basically yes - it is there to limit movements in the wrong direction when shunting as noted above by Chris ('Railwest').  However they were not universal in past times and the general understanding was that the shunt would simply set back as far as necessary to carry out the work in hand.  On a single line that almost inevitably meant a shunt going 'outside' (i.e in rear of) the Home signal but that was everyday working practice.

 

I can't think of any GWR example where an LoS board was used at a passing loop on a single line - in fact it was frequently necessary to shunt into the single line section and there was a very straightforward procedure for carrying it out although it's not relevant on an OES line of course.   Equally propelling through a section is a relatively straightforward procedure and would simply be authorised, with any restrictions, in the Sectional appendix.  for example on the Highworth branch it was permitted to propel up to 30 freight vehicles between Swindon Goods Yard and Stratton for the Pressed Steel sidings etc and propelling vehicles on what the WR called Table C2 worked lines (after 1960) which were a sorrt of equivalent to OES working in some respects was quite common due to lack of runround facilities or for other reasons such as gradients.

 

It was not unusual - although not particularly common - for cut back single lines to terminate without any sort of runround.  The best known example was probably Old Ynysybwl where the branch terminated at a halt as a single line with no run round and was worked by auto-trains as seen in this Museum of Wales photo -

 

https://museum.wales/collections/online/object/1240d80d-012e-3100-8c26-91dbdcc3dc4d/Locomotive-6401---Old-Ynysybwl-Halt-June-1952/?field0=with_images&value0=on&field1=string&value1=Rivers of Wales&page=618&index=7419

 

PS - Also in Wales, but at the northern end, was the branch line to Dyserth which had no runround capability at the terminus and was built like that.  And at one time had a passenger train service.

Edited March 6, 2020 by The Stationmaster
Add PS re Dyserth

[TheSignalEngineer]

On the LMS the Harborne branch was worked by propelling from the main line for the last few years of the goods service. I think this was following a breakaway which resulted in a few wagons of coal blocking the canal near Harborne Junction. It was still possible to run round at the terminus as it was the only way to access the Corporation depot.