Advice on signalling Northbridge

[Ch4lkst3r]

​Hi,

 

I'm slowly building my layout.  It is set in the 1960s towards the end of steam somewhere Western Region on the boundary with LM region to allow crossover of motive power.

 

I've attached the full plan of the layout plus my initial thoughts on the signalling.  I plan to have the signals working so have opted for 3 aspect colour lights on the main lines through the station controlled by a box at the station.  The junction at the bottom of the plan is lesser used so this box is still using semaphores (although this box is theoretical as it is off the layout as is the bracket signal).

 

Platform 2 is bi-directional to the end of the platform to allow reversal of trains.  Platforms 3/4 are single direction.  My understanding is that the signals at the right hand end of the platforms would display a yellow with number 4 route indicator if the semaphores at the junction weren't off (ie. these signals would be the distant for the semaphores).

 

The signal from Platform 4 has position lights to allow access to the headshunt.  Would these have been included on the signal in the 60s or would a separate GPL be on the ground?

 

Any comments and suggestions welcome.

 

Iain

Edited August 8, 2017 by Ch4lkst3r

[The Stationmaster]

Couple of points -

 

1.  There should be some trap points on the outlet siding from the engine shed area.

 

2.  If you are signalling to WR standards of the time (although the double slips in the running lines would be most unlikely for that period) only the signals on the through running lines would have a junction indicator (feather) and probably the one coming up from the junction at bottom right might have had a theatre type route indicator.  The other three reading from the platforms would have had stencil style route indicators.

[Ch4lkst3r]

Thanks for the feedback Mike.

 

I plan to fabricate a dummy trap point on the outlet nearest the platform.  I don't believe it needs one on the headshunt as the points would always be set away from the platform line unless the signal was cleared - is this correct?

 

I should have put that this is N gauge so obtaining things like working stencil indicators would be difficult (impossible?).  I was looking at using CR Signals for the colour lights with Dapol semaphores.  As I'm still in design stage if I was to swap the layout to LM region would this alter the use of feathers/theatre boxes?

[RailWest]

>>> don't believe it needs one on the headshunt as the points would always be set away from the platform line unless the signal was cleared......

 

Err.... I hope you intend to reverse the points before you clear the signal ! :-)

 

If the points in the headshunt are normally set for the yard, then yes - that would act as a trap.

 

Some random thoughts:-

 

1. Do you really need a signal from the yard to the headshunt?

2. The signal from the headshunt can read to the platform or the sidings off the double-slip or the sidings off the headshunt, three routes. Would a plain PLS suffice, or would it need a stencil route indicator?

3. The signal out of the sidings over the double-slip also has (at least) three routes available from it, so again perhaps a stencil indicator?

 

Perhaps Stationmaster might like to comment?

[TheSignalEngineer]

Apologies for the scrawl, but a few initial thoughts to open up the debate.

 

[The Stationmaster]

Apologies for the scrawl, but a few initial thoughts to open up the debate.

 

IMG.jpg

 

Unlikely to be theatre indicators if to WR 1960s standards where they tended to be unusual on signals where trains started from stand - stencil indicators were used instead on the Western (very different from the LMR way of doing things in those days).  Equally the WR was using position light junction indicators (feathers) for signalling running line divergences where through movements took place largely irrespective of line speed except where trains started from a stand (in which case stencil indicators were used although there were certain exceptions to this where there were too many routes to signal with JIs (e.g. Newport).

 

Equally - referring to Chris's comment in the 1960s route indicators on independent position light signals/GPLs on the WR were about as rare as hen's teeth - the first WR scheme which made any significant use of them was Westbury South in September 1978 and even then they were only used in very specialised locations and hence not on all PL signals with multiple routes from them.

 

Further following SE's sketch above the GPL reading from the long headshunt would almost inevitably have been a 'yellow light version' (instead of the usual red) in a WR 1960s scheme - e.g. as per two examples at Slough West dating from 1963.

[The Stationmaster]

WR colour lights - 1965 installation - with standard Reading design stencil route indicators, both have three stencil 'boxes for three routes

 

 

Stencil route indicator using experimental LED method so only requiring a  single box instead of (in this case) two with the older pattern of indicator

 

 

 

 

[Grovenor]

Stencil route indicator using experimental LED method so only requiring a  single box instead of (in this case) two with the older pattern of indicator

At that date i don't think there were any LED designs, not even experimental, what was just on trial and became common for some time before LEDs were Optical Fibre indicators where a bunch of fibres with lenses molded on the ends would be powered by a high power projector lamp.

Regards

[TheSignalEngineer]

At that date i don't think there were any LED designs, not even experimental, what was just on trial and became common for some time before LEDs were Optical Fibre indicators where a bunch of fibres with lenses molded on the ends would be powered by a high power projector lamp.

Regards

First Optical Fibre one I remember was a banner at Smethwick Rolfe Street, I think mid 1970s. 

[TheSignalEngineer]

Unlikely to be theatre indicators if to WR 1960s standards where they tended to be unusual on signals where trains started from stand - stencil indicators were used instead on the Western (very different from the LMR way of doing things in those days).  Equally the WR was using position light junction indicators (feathers) for signalling running line divergences where through movements took place largely irrespective of line speed except where trains started from a stand (in which case stencil indicators were used although there were certain exceptions to this where there were too many routes to signal with JIs (e.g. Newport).

 

 

Birmingham Snow Hill had Theatre indicators on the main platforms and through lines.

7912 at Birmingham Snow Hill (pjs,0673) by geoff7918, on Flickr

 

The bays had stencils.

Snow Hill in decline(9) 1969 by Stephen Burdett, on Flickr

[Ch4lkst3r]

Hi folks,

 

Thanks for the responses.  I've modified the plan as per the suggestions so it now looks something like this.

 

I've left the GPL coming from the yard onto the headshunt but am happy to remove.  I thought that there would be one to stop a conflicting move from the yard onto the headshunt at the same time as one from the platform.  The signal on the headshunt is now a yellow GPL so would be cleared for moves towards the platform.

 

I haven't put any stencils on the GPL's as I was following my understanding of some WR semaphore signalling where one ground disc has multiple moves and it's up to the driver/shunter to know where they are going.

 

I've added a new GPL on the through line so that locos off shed can access any platform.  I've only put the one in and not added any to the main aspects as suggested by TheSignalEngineer's plan as I'm keeping the shunt moves simple.

 

I've removed the two semaphores as per TheSignalEngineer's plan but does this now mean that I should have one as shown on the single line as the section signal for the box in the bottom right or would the arm on the bracket serve as that?

 

A couple of additional questions.  Firstly, did theatre boxes in the 60s work as they do know, ie. do the always show a letter to indicate route or would they ever be blank with the main aspect?

 

Secondly, what differences would there be if the station was LM region instead of WR?

 

Thanks for your advice

 

Iain

 

PS. Shame Snow Hill doesn't look like that anymore!

 

 

Edited August 8, 2017 by Ch4lkst3r

[RailWest]

If the GPL coming OUT of the headshunt is yellow, then - while the points are 'normal' for the yard - anything can shunt from the headshunt into the yard at any time. Seems contradictory therefore to still have a red GPL coming OUT of the yard onto the headshunt - you can stop outbound traffic by signal, but not inbound traffic.

[The Stationmaster]

Hi folks,

 

Thanks for the responses.  I've modified the plan as per the suggestions so it now looks something like this.

 

I've left the GPL coming from the yard onto the headshunt but am happy to remove.  I thought that there would be one to stop a conflicting move from the yard onto the headshunt at the same time as one from the platform.  The signal on the headshunt is now a yellow GPL so would be cleared for moves towards the platform.

 

I haven't put any stencils on the GPL's as I was following my understanding of some WR semaphore signalling where one ground disc has multiple moves and it's up to the driver/shunter to know where they are going.

 

I've added a new GPL on the through line so that locos off shed can access any platform.  I've only put the one in and not added any to the main aspects as suggested by TheSignalEngineer's plan as I'm keeping the shunt moves simple.

 

I've removed the two semaphores as per TheSignalEngineer's plan but does this now mean that I should have one as shown on the single line as the section signal for the box in the bottom right or would the arm on the bracket serve as that?

 

A couple of additional questions.  Firstly, did theatre boxes in the 60s work as they do know, ie. do the always show a letter to indicate route or would they ever be blank with the main aspect?

 

Secondly, what differences would there be if the station was LM region instead of WR?

 

Thanks for your advice

 

Iain

 

PS. Shame Snow Hill doesn't look like that anymore!

 

If you are going to do it LM style there will be some differences - for examples GPLs would be likely to have route indication (LMR style stencil indicators) and the stencil indicators on the main aspect signals would be theatre indicators.  Incidentally in some cases on the Western subsidiary (to main aspect) position lights did give an indication of route but that basically applied when they were used in the equivalent role to a Calling On signal or when reading into a line where the next 'signal' was a STOP board.

 

And yes - in the 1960s installations there were instances where a theatre route indicator could show no indication of route for the main (effectively the 'straight') route - its use was governed by speed differentials between the principal route and between the various divergent routes.  Definitely used in one place on the WR  - Signal R134 on the Down Relief Line approaching Reading station, commissioned 1965.

[luckymucklebackit]

Great name for a station!!  My Northbridge is already partially colour light signalled (just got it working again after wiring problems).  Best of luck with your project.

 

Jim

[Ch4lkst3r]

Hi folks,

 

Slight change of plan on signalling.  The S & T modernisation hasn't reached Northbridge yet (or in reality I've found Stephen Freeman at borg-rail.com and I think I'll be utilising his signal building skills!).  Therefore, I'm planning on having the whole layout using semaphore signals and my first attempt is below so I'm looking for comments (still WR).  I've lettered the signals for easier comments on specific ones.

 

Signal R is only theoretical as it's behind the backscene so won't exist.  Distant arms on C, E, F, G and R are all fixed due to the distance between the two signalboxes.  Signal D is a ringed arm on the exit from the TMD but this could be a ground disc?  Ground disc I is a yellow disc.

Edited September 19, 2017 by Ch4lkst3r

[RailWest]

I would suggest that the distance between the two SBs is irrelevant as to whether the distants are 'fixed' or not - it's a matter of the speed restriction etc. If you assume <40mph, then at least it will save you having to make them all work :-)

[Ch4lkst3r]

Well as that lines in the bottom right go off to the fiddle yard I don't want them going round there too quick or they'll be crashing into the bufferstops   We'll say it's less than 40mph.

[phil-b259]

Not sure about the need for signals O and Q

 

In a situation where the line stayed double (and signal P did not exist) then they do make sense, but with the line having been singled the function of signal O would move back to the appropriate arm on bracket signal R. Similarly the function performed by signal Q has been taken over by signal P.

 

This is because on a single line you quite clearly cannot have trains going both ways at the same time and trains will thus have to be held back at R if one is coming from P.

[Ch4lkst3r]

I agree about O and Q.  I had removed them on the last version with colour lights and shouldn't have been on semaphore version.

 

I was wondering today if ground disc B could be replaced by a small arm on bracket C but not sure as this only leads into the headshunt.  Any comments?

[The Stationmaster]

If you're going to signal it WR style you're basically ok as it stands but the following changes would make sense -

 

1. You can use a 3ft arm bracketed off the main structure instead of the disc signal B.

 

2. I'm not so sure about having Platform 2 signalled for train reversal with a bay alongside - there were no doubt some examples but it doesn't make too much sense without a trailing crossover at the left hand end of the station.

 

3. You seem well overdone for lower arm distants - although it means adding a signal you could adda stop signal with lower arm distant going round the curve but it would look overdone.  Far better I think to do away with the lower arm distants on all except the main through line signal (E).  The problem is the very short distance between those signals and the double junction where - in the real world - the Western would have had the splitting sign but that would probably look overdone (again) on a layout although it might be worth seeing if you could do it that way and have just a single stop arm for running movements on  C, E, F, and G.

[Ch4lkst3r]

Thanks for the advice Mike.

 

Changes so far to the plan:

Change ground signal B to 3ft arm on bracket C.

Remove signal F and make platform 2 single direction.

Remove signals O and Q.

 

Unfortunately it's not possible to place a signal by the double junction but although as you say it may look overdone I could place a stop signal parallel to L on the curve with a distant arm.  It would also act as the section signal (for box A) which for moves from the shed via signal D there isn't one and the next signal is signal N (home for box B).  The distant arms on C, E & G could then be removed (bracket F being no more).

 

I'm thinking of changing L & M to plain stop signals and then having a new bracket outside the box for platform 2/bay platform 1.  Any comments or am I overdoing it?  Would the arm for the bay platform be a shorter arm than the main in any case?

[The Stationmaster]

Thanks for the advice Mike.

 

Changes so far to the plan:

Change ground signal B to 3ft arm on bracket C.

Remove signal F and make platform 2 single direction.

Remove signals O and Q.

 

Unfortunately it's not possible to place a signal by the double junction but although as you say it may look overdone I could place a stop signal parallel to L on the curve with a distant arm.  It would also act as the section signal (for box A) which for moves from the shed via signal D there isn't one and the next signal is signal N (home for box B).  The distant arms on C, E & G could then be removed (bracket F being no more).

 

I'm thinking of changing L & M to plain stop signals and then having a new bracket outside the box for platform 2/bay platform 1.  Any comments or am I overdoing it?  Would the arm for the bay platform be a shorter arm than the main in any case?

 

Generally ok.

 

Just realised that Q should have two arms (ok one above the other on a single post) as it has two routes.

 

I like the idea of the signal opposite L but you could legitimately still keep the lower arm distant on E - but only on E - if you want.

 

Changing L & M as you suggest is a good idea - typically Western (for post 1920s)!   Both arms would be full length as the Bay is a passenger line.

 

I wouldn't do away with Q - as you have it the result is typically Western with a running stop signal to protect each point in succession (and some folk thought the NER was oversignalled - nonsense when compared with the GWR). 

Edited September 21, 2017 by The Stationmaster

[Stephen Freeman]

Mike,

3 things I'm not clear on:

1) Not sure how Q should be bi-directional, perhaps I've missed something.

2) Given the period being WR rather than GWR, should B not be a disc, granted perhaps elevated, as I seem to remember you saying that the  miniature arms started to be replaced in the 1930s. (Discussion on Brent/Stoke Courtnay I think)

3) Signal I - I am not sure that WR or GWR for that matter ever had black and yellow ground signals, the only difference being the light when the signal was at danger. I thought the black and yellow ones were just an aberration of preservationists/SR. Am I wrong?

[Ch4lkst3r]

Mike, I'm not sure what you mean about Q either.  There is only one route from there under the road bridge and to the fiddle yard.

 

Stephen, I think 3ft arms are fine.  I know miniature arm shunting signals were replaced or covered up by discs.

There is definitely a yellow/black ground disc at Worcester Shrub Hill as shown here (https://signalbox.org/signals/gw.htm) although I only drew it that way so that the fact it had a yellow band showed up on the diagram.

 

Version 2 below with changes:

Ground disc B replaced by 3ft arm on new bracket on C.

Bracket F removed and platform 2 now single direction.

New signal T on curve with distant and stop arms.

Signals L & M now single stop arms and new bracket S outside box for moves to platform 2/platform 1(bay).

I've left O and Q on.  I agree with Mike as per running stop signals as I'm used to seeing these around Worcester.  I put O on as this is similar to Malvern Wells where the line singles for the tunnel and the last signal in the down direction is before the single line.  So should O stay or go?

 

Signal construction of tubular posts with silver/aluminium painted posts?

 

 

[TheSignalEngineer]

That is looking rather GW-ish. I'm not convinced that O and Q really serve any purpose unless a train or light engine could stand at them and not block the junction/single line points so something can pass behind. 

 

The other consideration is how the single line is worked. If Token, Tablet or Train Staff this will be picked up and dropped off at the box so there I don't see any benefit of them being there. The token needs to be out to clear O, so if a train stopped at Q the Fireman would have to walk forward to give up the token to free up the single line or an auxiliary token instrument provided on site. If worked by Track Circuit with Direction/Acceptance levers then there may be a benefit.

 

Would it be an advantage to put the single line points as close to the bridge/tunnel as possible and signal P to be off-scene? It may give a bit more standage at O and Q if they are provided.

Edited September 21, 2017 by TheSignalEngineer