Signalling Holcombe, S&DJR Nettlebridge Valley Branch

[slow8dirty]

Evening all,

 

I've been building my Holcombe layout on and off for the last year (stop sniggering at the back there), and I am finally at the stage of needing to fine tune my plans for signalling the layout before I do any more to the trackwork. Thanks to many fine members of the forum collective who have helped with past projects, which is why I'm at the stage where I can at least present something for discussion. Hopefully someone who knows can point me in the right direction, again!   

 

Ok preamble over heres what things look like sizewise.

 

 

The two pics above are taken from nearly half way along looking in either direction. The longest planned passenger and good trains are sat in what will be the main platform road and loop, the upright oil pen by them is the rough position of the platform starters. I've posted these to help people get an idea of proportion in case looks and compromise have to take priority over accuracy, not becuase I'm proud of bare plywood!

 

The main design plan

 

 

And finally, if your still awake, my poor attempt at a signalling plan

 

 

I'm fairly ok with most of what I've drawn I think,  , Its a fairly basic BLT but the main problems I have are how to signal the routes over the double slip into and from the goods yard  ( a modellers contrivance I know). I'm sure there are many things I never thought of so I'd be very glad of some folks opinions on where to go from here. I also have a growing list of questions re point rodding but that will wait until we know whats where.

 

Oh in case it helps, the layout is meant to be a fictional station on the Nettlebridge Valley branch of the Somerset and Dorset Joint Railway, (joining the Bath Extension at Binegar Junction  ) set during the lattter half of the 1950's.

 

Thanks for reading

 

Matt

[RailWest]

Some quick questions!

 

1. When does your 'history' assume that this station was built?

2. Is the 'scenic break' on the left an overbridge or a tunnel?

3. What is the distance from the edge of that bridge/tunnel to the first point (as reached by an approaching train)?

[slow8dirty]

Hi Chris, thanks for stopping by.

 

1. When does your 'history' assume that this station was built?

A: 1874/75, either as part of the Bath extension or very soon afterwards.

 

2. Is the 'scenic break' on the left an overbridge or a tunnel?

A: It will be an ordinary road overbridge, pardon my draughting skills.

 

3. What is the distance from the edge of that bridge/tunnel to the first point (as reached by an approaching train)? 

A: There is space for one loco or one loco and wagon depending upon type.

 

Matt

[RailWest]

OK - will try to post a sketch and some notes over the weekend.

[bécasse]

As you have probably noticed, the S&DJR was a bit short on what might be described as normal BLTs, so it is necessary to look at what the L&SWR (which was responsible for the Joint Line signalling) was doing at its small terminals in the south west.

 

This suggests that you have got it largely right but:

 

1. You don't need the shunt signal going towards the buffer stops on the run round loop, it isn't impossible though and if you do have one there it should be yellow from about 1925 on. (However, as Chris has pointed out elsewhere, the S&DJR was somewhat slow in actually applying yellow paint and glass!) The release crossover point wouldn't have had a facing point lock.

 

2. You definitely do need a single shunt guarding the exit from the run round/yard to the main line - this would have been mandatory. Again it should be yellow post-1925ish.

 

3. I think that the signal permitting access from the bay to the loco shed is likely to have been a disc, either on the bracket platform or bracketed out from the side of the main post, rather than a subsidiary arm.

[slow8dirty]

OK - will try to post a sketch and some notes over the weekend.

 

Thankyou Chris, much appreciated.

 

 

1. You don't need the shunt signal going towards the buffer stops on the run round loop, it isn't impossible though and if you do have one there it should be yellow from about 1925 on. (However, as Chris has pointed out elsewhere, the S&DJR was somewhat slow in actually applying yellow paint and glass!) The release crossover point wouldn't have had a facing point lock.

 

2. You definitely do need a single shunt guarding the exit from the run round/yard to the main line - this would have been mandatory. Again it should be yellow post-1925ish.

 

3. I think that the signal permitting access from the bay to the loco shed is likely to have been a disc, either on the bracket platform or bracketed out from the side of the main post, rather than a subsidiary arm.

 

Thankyou, bécasse, lets see..

1: So, assuming the release crossover is controlled from the box the disc on the loop itself is an option. Chris has discussed with me before the S&Ds situation with yellow paint . No FPL on the loco release, happy with that. Would there still be a ground signal controlling movement from the platform road loco release across to the loop? (If I'm making sense).

 

2:Now this is what has been confusing me, but having just looked at the plan for Wells and seeing ground signals controlling exits from two sidings I think I understand. The yellow( or white that locally just gets treated as a yellow) is situated between the loop and the goods yard line, yes?

 

3: Thanks, reckon Ill go with a disc on a bracket.

 

 

Thankyou both,

 

Matt

[bécasse]

Thankyou Chris, much appreciated.

 

 

Thankyou, bécasse, lets see..

1: So, assuming the release crossover is controlled from the box the disc on the loop itself is an option. Chris has discussed with me before the S&Ds situation with yellow paint . No FPL on the loco release, happy with that. Would there still be a ground signal controlling movement from the platform road loco release across to the loop? (If I'm making sense).

 

2:Now this is what has been confusing me, but having just looked at the plan for Wells and seeing ground signals controlling exits from two sidings I think I understand. The yellow( or white that locally just gets treated as a yellow) is situated between the loop and the goods yard line, yes?

 

I will reply to these in reverse order.

 

Firstly I will deal with the (yellow) shunt signal at the exit from the run round loop and goods yard. On double slips, the pairs of point blades at each end always work in unison with each other - therefore the two pairs of blades at the terminal end will select the route (from both the loop and yard) towards either the head shunt or the main line and the two pairs of blades at the throat end will select the route (from both the head shunt and the main line) towards either the loop or the yard. The former set of blades will be worked by the box, effectively as a trap, so almost certainly worked by the same lever as the point of the main line towards the loop/yard (think of it as two superimposed crossovers). The latter set of blades will be worked by hand lever - and will probably normally be set towards the loop as that route will be used the most, but there is no "formal' normal setting. The (yellow) shunt signal is sited at the toe of the point blades worked by the box, probably on the side away from the main line since there appears to be more space and the sighting from both the loop and the yard will be better. It is cleared whenever a movement is required from either the loop or the yard on to the main line. Even if it is an old-style S&D red flap signal it won't be cleared for movements towards the head shunt because it doesn't apply to such movements, remember that shunt signals only apply to those movements which they are intended to signal.

 

Secondly I will deal with the signalling for the engine release crossover. This is more complicated because the L&SWR had nearly as many variations as they had engine release crossovers. In every case, the engine release crossover was worked by the box, either directly or indirectly by a release for a local crossover - the latter is inappropriate here, so I won't consider it further, and I will assume that the crossover is worked directly by a lever in the box. The simplest arrangement was post the SR alterations at Seaton and that was the provision of a fpl (but not locking bar) on the point in the platform road with no shunt signals - possible, but perhaps a touch modern for an ex-S&D BLT. The most common L&SWR arrangement was to provide shunt signals at one or both ends of the crossover but no fpl. In practice, a shunt signal seems to have only been provided on the loop road if there was some good reason for it, and so the commonest arrangement was just a shunt signal at the toe of the point in the platform road. In theory, as well as being pulled off for movements over the crossover (i.e. for a loco to run round), it should have been cleared (detecting that the point was set for the platform road) before the platform starter could be cleared BUT the L&SWR don't seem to have done so and the BoT Inspecting Officers don't seem to have raised the issue. It is this single shunt signal with no fpl option that I am recommending to you. It is simple and no one can say "that's wrong" because prototype examples exist.

[slow8dirty]

EUREKA!

 

I make no apologies for internet "shouting", thank you for a very patient and comprehensive reply, I had to re-read the double slip example a couple of times and then read it again whilst staring at the actual slip in question, (you should have seen me trying to wire it up), but it makes perfect sense now. I should have started this thread earlier, Ill do a slight rewire now to operate those two motors off of the same panel switch.

 

Thanks

 

Enlightened of Somerset.

[slow8dirty]

Ok where we are so far

 

 

All suggestions posted  added so far, all ground signals are marked as disc so far, but am I correct in thinking the only examples of yellow ground signals on the S&D were miniature ground semaphores?

 

I'm also wondering about the location of the shunt signal ringed at A. would its location be at the far side of the bridge by the outer home or should it be adjacent the toe of the points at B, bearing in mind there is a tad more than a loco length between the overbridge and the points.

 

I'm guessing the advanced starter would control how far shunt movements went up the line, or would there be a limit of shunt board?

 

Thanks,

 

Matt

 

[beast66606]

 

 

remember that shunt signals only apply to those movements which they are intended to signal.

 

 

Cough - ALL signals only apply to those movements which they are intended to signal.

 

I think what you meant was

 

Yellow shunt signals can be passed at danger for routes to which the signal does not apply.

 

Often saying less and building up to the answer is more useful than simply trying to demonstrate knowledge - if someone asked about LNWR/LMS/LMR signalling I could spend weeks (509 of them) typing an answer - whether the asker would understand it is another matter. 

[RailWest]

Given what has been discussed already, I'm not sure if there is much that I can add at this stage.

 

Personally I would have made the entrance points for the loco shed road lie normal for the bay, as the bay is a passneger line, but it's probably 50/50 :-)

 

>>>am I correct in thinking the only examples of yellow ground signals on the S&D were miniature ground semaphores?

 

AFAIK yes. There was one alteration at Glastonbury in the 1950s for which I have yet to see a picture, but if you assume that yours were 'updated' at an earlier date then I would go for the mini-arm type.

 

>>>I'm guessing the advanced starter would control how far shunt movements went up the line.......

 

Essentially yes, tho' in practice you could shunt past it anyway with the appropriate authority.

 

>>>>would there be a limit of shunt board?

 

NO - not on single-lines, as such things existed for 'wrong road' movements. [ignore what you may see ons ome heritage lines today ]

[slow8dirty]

Thanks for coming back to this Chris, good to know you've had a look over things as well.

 

Would the shunt signal at A remain the other side of the scenic break, for sighting purposes or would it be adjacent the point to the yard? Opinions folks.

 

Matt

[The Stationmaster]

Thanks for coming back to this Chris, good to know you've had a look over things as well.

 

Would the shunt signal at A remain the other side of the scenic break, for sighting purposes or would it be adjacent the point to the yard? Opinions folks.

 

Matt

We've had one recent example (SR as it happens) on here where there was a disc shunting signal at both locations   It really does depend on distance and how far back the Home Signal is but you might find it operationally convenient and useful to have a disc at the toe of the points (which would be cleared for all movements including running movements such as arriving trains.

[RailWest]

Again a personal view on something which could be 50/50, but given the relatively short distance (unlike Seaton) between the Homes and the toe of the facing point, I would have a disc at the points and omit the one at the Homes.

 

I think it also depends to what extent the builder wants a layout that, although based in the 1950s, still reflects its 'old' S&D heritage rather than some 1930s SRly modernisation.

[slow8dirty]

Thanks guys,

 

its the details that are coming out backed up with years of experience and research that you just cant replace with a peco "shows you how" booklet. 

 

Quite happy that that prototype principles can be applied to my trainset, I've a feeling that the point rodding is where things are going to fall down.

 

Heres a rough plan of rodding runs from the box in its current position. I thought my rtr track looked quite good till I took this picture!

 

 

 

Its probably all wrong but the one that most concerns me the most is the one Ive drawn in green going to the loco rd trap, the Bay point and it's FPL?

 

Mentioning FPLs, Economical Facing Point Locks isn't of relevance here is it?

 

Matt

(Nearly coming to the end of my knowledge drain!)

 

 

 

 

 

[RailWest]

>>>its the details ......that you just cant replace with a peco "shows you how" booklet.

 

What am I bid for a 'boxed set' ????

 

>>>Economical Facing Point Locks isn't of relevance here is it?

 

Sorry, no :-( Off-hand I can't recall a single one on the S&D.

 

Could we see the rest at the RH end please?????

 

PS. I hope you're not going to use a 'Shillingstone' box????? :-)

[bécasse]

Cough - ALL signals only apply to those movements which they are intended to signal.

 

I think what you meant was

 

Yellow shunt signals can be passed at danger for routes to which the signal does not apply.

 

 

Actually I didn't mean to say yellow shunt signals because the point I was trying to make was that when red shunt signals were first introduced they usually could be passed at danger unless the route to which they applied was set - very much like yellow shunts in later days.

 

On the vast majority of railways in the Victorian era shunt signals were relatively rare because the BoT normally only required them to be installed to control exits from sidings on to running lines. Other moves, across crossovers, entry to sidings, etc were authorised by hand signal. Some railways (and as it happens the L&SWR was one of them) had started to install shunt signals more widely from the 1880s, others (and the L&NWR is a good example) didn't. Some railways (e.g. the GWR) tended to install point indicators which looked much like shunts but were directly linked to the adjacent points and worked in unison with them. Gradually even the non-believers realised that there were many situations where hand signalling was difficult and installing shunts greatly facilitated efficient working, and eventually shunts became half-way universal. Even then there remained many shunt moves, especially very close to boxes, which didn't have fixed signals.

 

In situations where the only shunt signals guarded exits on to running lines, it was normally accepted that the signal only applied to such moves and that they could be passed "on" when the route was set for the head shunt (or w.h.y.), indeed I suspect that a study of locking tables would reveal that they often couldn't be cleared unless the route out was set. Of course, post-1925 these signals should all have been painted yellow and had yellow glass fitted, but observation suggests that many obscure locations got missed, perhaps to save the cost. If they had passed the signal "on" pre-1925, drivers almost certainly continued to do so post-1925. Drivers weren't stupid, unless they were "working to rule", they interpreted the Rule Book sensibly but they never compromised on safety. In the old days, safety meant doing tasks the safe way, not ticking boxes.

[bécasse]

Again a personal view on something which could be 50/50, but given the relatively short distance (unlike Seaton) between the Homes and the toe of the facing point, I would have a disc at the points and omit the one at the Homes.

 

I think it also depends to what extent the builder wants a layout that, although based in the 1950s, still reflects its 'old' S&D heritage rather than some 1930s SRly modernisation.

 

I am not sure that I agree with Chris on this one, although, as he says, it is a bit 50/50 - and there isn't really an S&D example to give guidance.

 

My reasoning is based on two points:

 

Firstly, I assume that you might want to bring an arriving freight straight into the loop road because the platform road is occupied. If you do, you really need a signal for it (with the over bridge in the way, a hand signal from the box isn't really sufficient) and the shunt provides that signal. If you don't, end of argument.

 

Secondly, a shunt signal at the toe of the facing point is going to be a running shunt (i.e. it has to be cleared before either of the home signals can be cleared) and as such can only be cleared with the fpl bolts in. On the assumption that the fpl is fitted with a locking bar, that means that the shunt won't be at the actual toe of the point but a locking bar length (say 160mm or around 6ins in OO) further back which starts to eat into the already short distance back to the homes. If there isn't a shunt signal here, then the signalman would leave the bolt out, throw the point as soon as the loco is clear of it and then give the loco crew a green hand signal to come back onto the train. However, it was worth noting that this tandem point, together with the point giving access to the loco shed, may well have been track-circuited rather than being fitted with locking bars - and this would allow the shunt signal to be at the toe of the point (so back to point one.)

[beast66606]

Some railways (and as it happens the L&SWR was one of them) had started to install shunt signals more widely from the 1880s, others (and the L&NWR is a good example) didn't. 

 

The LN&WR installed shunts where the considered them necessary, exactly like any other company (except maybe the NE). I have knowledge of lots of LNWR layouts and can't recall any which were particularly lacking in shunt signals, aside from moves which would be rarely performed. I also own a genuine LNWR signal box diagram which is very well provided with ground signals. Typically quieter lines with connections near to the box relied on hand signals but then that applied on other railways.

 

I've never heard of shunt signals being ignored when the driver decided it didn't apply to the route he was taking - a very bizarre method of working and fraught with danger, even in those days were danger was run of the mill - however assuming it's correct, if you say something which only applies to a limited amount of time - in this case the early days of the railways then say so - your comment was not qualified with any time frame, it states in black and white

 

 

remember that shunt signals only apply to those movements which they are intended to signal.

 

which is wrong.

[slow8dirty]

..........

 

Sorry, no :-( Off-hand I can't recall a single one on the S&D.

 

Could we see the rest at the RH end please?????

 

PS. I hope you're not going to use a 'Shillingstone' box????? :-)

 

Happy with that re: FPLs , ta

 

heres a poor picture of the RH end ( the tie bars of the point at the Right edge of picture are those of the double slip for orientation purposes), I can knock a proper plan up if people are still having trouble understanding. The two trains are stood over the release crossover.

 

Re, the box, I think we've had this conversation before Chris, earlier, over in the build thread. Th e RTP buildings were chosen as way of seeing if a quick build could be done effectively using the new crop of buildings as a reaction to things not happening quickly for me. Ok, the quick thing has definitely dropped by the wayside, but I'd still like to stick to the principle as it were.

The upshot of it was that I could use it BUT it would need a very large dose of modellers license, and whilst still unlikely, it would be more plausible for a surviving type 1 in the North to be a brick base. Does that cover it or are there more problems with this method?

 

Cheers

 

Matt

[slow8dirty]

I am not sure that I agree with Chris on this one, although, as he says, it is a bit 50/50 - and there isn't really an S&D example to give guidance.

 

My reasoning is based on two points:

 

Firstly, I assume that you might want to bring an arriving freight straight into the loop road because the platform road is occupied. If you do, you really need a signal for it (with the over bridge in the way, a hand signal from the box isn't really sufficient) and the shunt provides that signal. If you don't, end of argument.

 

Secondly, a shunt signal at the toe of the facing point is going to be a running shunt (i.e. it has to be cleared before either of the home signals can be cleared) and as such can only be cleared with the fpl bolts in. On the assumption that the fpl is fitted with a locking bar, that means that the shunt won't be at the actual toe of the point but a locking bar length (say 160mm or around 6ins in OO) further back which starts to eat into the already short distance back to the homes. If there isn't a shunt signal here, then the signalman would leave the bolt out, throw the point as soon as the loco is clear of it and then give the loco crew a green hand signal to come back onto the train. However, it was worth noting that this tandem point, together with the point giving access to the loco shed, may well have been track-circuited rather than being fitted with locking bars - and this would allow the shunt signal to be at the toe of the point (so back to point one.)

 

This innocent, nearly forgotten little ground signal is proving most interesting.

[Izzy]

And of

 

This innocent, nearly forgotten little ground signal is proving most interesting.

 

 And of course, once you have worked out exactly what point rodding runs you need, then there's just the fun of working out exactly where those pesky rodding compensators need to be.........

 

Izzy

[The Stationmaster]

This innocent, nearly forgotten little ground signal is proving most interesting.

Could be even more interesting than you think as it could be at the point toe and the facing point lock bars would run through the point as either inside or outside bars (eithet inside or outside the running rail that is).  And if that disc at the toe of the three way was there as a 'leading disc' and used for shunting purposes then it couldn't have the lock bar in rear of it (for reasons already explained) so the lock bars would have to be in advance of it and run through the points themselves.

 

So nothing to stop you putting it at the toe of that point should you so wish.

[RailWest]

Looking further into the matter of shunt signals.......if one can extrapolate from Wells, even when the 'from Glastonbury' Home was moved further from the box there was still no shunt disc at all for moves into the loop! Going further afield to Padstow (to use a L&SWR example), when the Down home was moved out from being near to the loop points, the disc there became a running shunt but no disc was ever added at the Home despite the fact that AFAIK it was out of sight of the box!

 

On the box structure - this seems to crop up so much these days (one result of the Bachmann model!) that I forget on which thread it may have been mentioned before :-( The only SDJR Type 1 found north of Evercreech Jcn was at Evercreech New and that was stone-to-floor, whereas those at Pylle etc were brick-to-floor. I would suggest that you adopt whatever material (brick/stone) you use for the station buildings.

 

However, it all comes down to chronology and geography. If the branch was built c1874/5, then I would suspect that the signalling would have been done off the back of the Saxby & Farmer contract, so probably a small (wooden?) box on the plaftorm and certainly no shunt discs, and almost certain to have been replaced at some later date. If built late-1970s, then probably a SDJR Type 1, but again no shunts.

 

I can envisage a scenario where the station was built with one platform face only, but then enlarged as traffic increased, perhaps after doubling of the main line? The new work would require additional signalling, with the enhanced BoT requirements by that time, so /perhaps/ a replacement box to the Type 2 style (which you will have to build yourself unless Bachmann finally makes models of MSN!). If you left such an upgrade to later (c1900-10), then you might envisage a S&D Type 3 box, in which (for brick) you might be able to adapt the 'Bude' model from Kernow.

[slow8dirty]

Thanks Chris,

 

Thats expanded upon what you've suggested before and is really helpful, I've been thinking about the base recently and the info has added impetus to that.