Signalling for Begbrooke - any comments please?

[The Great Bear]

Just trying to get my head around the bracket signals, what is correct practise, which may not necessarily be what my prototype had.

 

What determines which route is the bracket (if there is only two arms) - is it based on what is the higher "class" route or the "diverging" route. I'm thinking in particular of nos.8 and 6 which are drawn as the prototype, which had 6 as being a small arm on small bracket - looks like a retrofitted bodge. Should it really be like 7 and 4 - even if the route back onto the mainline is really the diverging route and most traffic would go straight on up the branch (and on that basis 4 would be the bracket not 7). Hope this makes sense.

 

Thanks

 

Jon

[Miss Prism]

They're correct as drawn, Jon. A lower arm (on a bracket) usually indicates a divergence from the 'straight on' route. Hence 4 is straight on for the branch, but 7 diverges to the branch siding. Similarly, 8 is straight on for the branch, but 6 diverges to the main.
 

[The Great Bear]

They're correct as drawn, Jon. A lower arm (on a bracket) usually indicates a divergence from the 'straight on' route. Hence 4 is straight on for the branch, but 7 diverges to the branch siding. Similarly, 8 is straight on for the branch, but 6 diverges to the main.

 

 

Hmm, thanks but not sure on that...my understanding is that 7 reads to branch, 4 for the route to the mainline and in-line disc 25 reads to the siding. Which would then mean the bracket arm on the signal was the wrong way around?

 

Similarly going other way toward Begbrooke from Marlingford 40 and 36 should be on a left bracket, not 28 on a right bracket.

 

Looks like quite a few anomalies in the prototype. I'm inclined to just follow that, but curious for my education to know if it was "right" or not.

 

Once again thanks

 

Jon

[The Stationmaster]

Hmm, thanks but not sure on that...my understanding is that 7 reads to branch, 4 for the route to the mainline and in-line disc 25 reads to the siding. Which would then mean the bracket arm on the signal was the wrong way around?

 

Similarly going other way toward Begbrooke from Marlingford 40 and 36 should be on a left bracket, not 28 on a right bracket.

 

Looks like quite a few anomalies in the prototype. I'm inclined to just follow that, but curious for my education to know if it was "right" or not.

 

Once again thanks

 

Jon

Normally the highest elevated arm applied to the principal (or most important) route then the relative elevation of the arms descended until the lowest one applied to the least important route.  It is usually the case that the highest arm applied to the 'straight' route but this is not always so and it is definitely not the case that the highest arm necessarily applied to the fastest route although, again, it usually did.

 

As far as the disposition of arms on brackets in relation to the main upright is concerned the basic rule is that there wasn't one.  GWR bracket styles varied over the years but the Company was never a great lover of balanced brackets especially in the 20th century although some examples from teh 19th century lasted a long time and there were occasional later ones.  The deciding feature was the site (for the main upright) and the siting (of the arms) and ground conditions could play as importanta  part as any other factor in the factors involved in deciding a particular signal form to suit a site.

[Miss Prism]

Hmm, thanks but not sure on that...my understanding is that 7 reads to branch, 4 for the route to the mainline and in-line disc 25 reads to the siding. Which would then mean the bracket arm on the signal was the wrong way around?

 

Similarly going other way toward Begbrooke from Marlingford 40 and 36 should be on a left bracket, not 28 on a right bracket.

 

Ah yes, see what you mean - I misread the diagram and had forgotten about 25. Perhaps a more typical arrangement for the bay starter could have been a single arm with a route-indicator box.

 

The arrangement of the bay home (40/28/36) is perhaps dictated by the post being on the right-hand side of the track - if the bracket had been overhanging the main, maybe there was a danger of 40 being misread as a signal for the up main. Having said that, I'm now confused as to what 40 and 28 and 36 relate to.

[The Stationmaster]

 

Ah yes, see what you mean - I misread the diagram and had forgotten about 25. Perhaps a more typical arrangement for the bay starter could have been a single arm with a route-indicator box.

 

The arrangement of the bay home (40/28/36) is perhaps dictated by the post being on the right-hand side of the track - if the bracket had been overhanging the main, maybe there was a danger of 40 being misread as a signal for the up main. Having said that, I'm now confused as to what 40 and 28 and 36 relate to.

 

If I'm looking at the right diagram 40 reads to the Up Main, 36 is the Calling On to the Up Main, and 28 reads to the bay.

 

On the lever leads 40 would be Up Branch Inner Home to Up Main  Home, 36 Up Branch Inner Home to Up Main Calling On, and,  28 Up Branch Inner Home To Bay

[The Great Bear]

I would think that in the real world it was about 100 yards from the one in rear - so quite enough distance between them for GWR tastes (the NER wasn't the only railway of signal profligacy) and I suspect that it main purpose was to protect and prove the Branch end toe of the (real) No.37 crossover complete with a facing point lock bar immediately in advance of it.

 

You could possibly get away with a 'through the bridge hole' view of the signal and in normal circumstances most trains would in any case have found it 'off' when they got to it I would think.

 

How about something like this? (Doing another "easy" signal in between getting to grips with the more complex - for me - ones.)

 

 

That was 12'6" above rail, perhaps could be a tad lower still?

[The Stationmaster]

How about something like this? (Doing another "easy" signal in between getting to grips with the more complex - for me - ones.)

 

 

 

That was 12'6" above rail, perhaps could be a tad lower still?

I suspect the arm would be foul of gauge if it was any lower - ought really to be a centre pivot arm if clearances are tight but that arm is ok if there is enough space.

[The Great Bear]

As shown in the layout thread I'm slowly getting on with making the signals. Some from the SRS signal diagram I can see have track circuit diamonds and there are codes like 2T and 2AT. These I think relate to the lever of the signal or point and the A is for circuit in advance (in direction of travel) of that signal, is that the correct? Is there any equipment one would see trackside related to the circuits, discernable in 4mm scale?

 

Also, completely different question: when might a signal box shift for box like Kidlington start and how long a shift, 12 hours?

 

Thanks

 

Jon

[The Stationmaster]

As shown in the layout thread I'm slowly getting on with making the signals. Some from the SRS signal diagram I can see have track circuit diamonds and there are codes like 2T and 2AT. These I think relate to the lever of the signal or point and the A is for circuit in advance (in direction of travel) of that signal, is that the correct? Is there any equipment one would see trackside related to the circuits, discernable in 4mm scale?

 

Also, completely different question: when might a signal box shift for box like Kidlington start and how long a shift, 12 hours?

 

Thanks

 

Jon

GW track circuit nomenclature had somem pecularities (well to an operator their pecularities!) - the XXT track circuits are usually through something, basically facing points.  xxAT track circuits seem generally to be found in rear of the signal whose number they carry - illogical in relation to the normal definition but perhaps it made sense to a signal engineer who worked out the track circuit was occupied in advance (time wise) of a train arriving at the signal whose number it carried (sounds feasible?).

 

I'm off to delve out the 'box hours hoping that 1947's will be ok?  In 1947, and 1938, Kidlington was open continuously although it did have a closing switch.  Normal shift length would be 8 hours except possibly on Sundays when they might have done 12hrs to give one man a day off while not letting the Reliefmen in, 12 hour turns mightw ell have been worked in teh event of illness or vacancies when no Reliefman was available.

 

Track circuits, other than very near the signalbox, would require at least one location cupboard (for the batteries) and possibly even one at each end.

[The Great Bear]

I'm off to delve out the 'box hours hoping that 1947's will be ok?  In 1947, and 1938, Kidlington was open continuously although it did have a closing switch.  Normal shift length would be 8 hours except possibly on Sundays when they might have done 12hrs to give one man a day off while not letting the Reliefmen in, 12 hour turns mightw ell have been worked in teh event of illness or vacancies when no Reliefman was available.

1947 would be perfect, thanks Mike. (Aside from general curiosity , reason for query is that inspired by article on Churston in MRJ I thought I'd do bit more work on a running order for the layout and thought start of box shift might be good place to start.)

[The Stationmaster]

1947 would be perfect, thanks Mike. (Aside from general curiosity , reason for query is that inspired by article on Churston in MRJ I thought I'd do bit more work on a running order for the layout and thought start of box shift might be good place to start.)

Standard changeover times were 06.00, 14.00, & 22.00.  In modern times it was not unusual for these to be varied a bit by local arrangement and often they were varied a bit informally but as far as I've ever seen they kept to, or pretty close to those official times in earlier years.  So your 'day' should sensibly start at 06.00 unless there's a train about a little bit before then that makes a sensible looking starting point with a string of movements following it that runs through the 06.00 changeover.

 

Just to show how that latter situation could work out in a couple of freight marshalling yards where I worked at various times it was usual for the night shift to stop for breakfast sometime around 02.00 - 03.00 (obviously this could vary between yards depending on gaps in the work).  After breakfast (and still of course very much night time) the phraseology became 'this morning' while anything before breakfast was 'last night'.

[MarkAustin]

Possibly a silly question: "White light disc", does that do exactly what it says on the tin: a normal ground disc but with different coloured spectacle glass (which one does the white replace?)

 

Possibly an even more silly question: does the same apply then to signals lets say on an engine release crossover or in case or Marlingford if I hadn't chickened out on fully signalling it the signal from the loop back to the branch, because it needs to passes if on to get to the cattle dock.

The White replaces the Red. This was unique to the GWR (as far as I know) and was used to control movements off the main line to sidings. White meant route set to main line; green route set for siding.

 

Mark Austin

[MarkAustin]

I agree that signal 41 is badly sighted. I suspect that, if it cannot be relocated, it would be a on a short post and a center pivot "somersault" signal to avoid fouling the lien. The GWR wasn't a great user of these, but did use them in these circumstances. There was one on Cockett station where the platforms come right up to a rather high overbridge, and the Down starter is beyond the bridge.

 

Mark Austin

[The Stationmaster]

The White replaces the Red. This was unique to the GWR (as far as I know) and was used to control movements off the main line to sidings. White meant route set to main line; green route set for siding.

 

Mark Austin

Regrettably that is not entirely correct, and in some respects slightly misleading.  The full explanation can be found in Post No.23 on the first page of this thread but suffice to say here that it also applied at ground shunting signals at crossovers between running lines and of course it wasn't universal in application depending on the signalbox locking.

[The Great Bear]

 

Would no.33 be a white or red light disc? I am thinking, if it was adjacent to the point (other recent thread on here) then would it be white light or to the rear adjacent to the signal 41 a red light one. Does the FPL affect this?

 

Thanks

 

Jon

[The Stationmaster]

1. It should really be adjacent to the signal (No,41).

2. Technically on normal application of what appeared to be the criteria it should have a red light and when you think about it logically wouldn't have had a white light as that could have meant that it gave authority to pass No. 41 at danger!

 

The FPL makes no difference in some respects but does when you relate it to signal No.41.

 

All looking rather nice!

[The Great Bear]

Another question , arising as I am working through making the ground signals:

 

Do discs that face the signal box have no backlight, same as  the post mounted semaphores? Perusal of some photos in books inconclusive, ones to hand only show front view.

 

(Difficulties in mounting and aligning the lamp with led mean it would suit if answer was yes, though not insurmountable just my solution is not pretty.

 

Thanks

 

Jon

[The Stationmaster]

Another question , arising as I am working through making the ground signals:

 

Do discs that face the signal box have no backlight, same as  the post mounted semaphores? Perusal of some photos in books inconclusive, ones to hand only show front view.

 

(Difficulties in mounting and aligning the lamp with led mean it would suit if answer was yes, though not insurmountable just my solution is not pretty.

 

Thanks

 

Jon

1.  They all have backlights, standard lampcases all seem to have come with backlights.

2.  I think they all came with back blinders as that was part of the way the constituent parts were made - the final tubular steel design definitely had back blinders (not much help to you I appreciate) and I'm reasonably sure - but always happy to see photographic evidence to the contrary that the interwar design using a square lamp case did as well.  And I think the earlier patterns did.

 

BUT the backlights were very small, presumably to avoid any possibility of confusion with white light ground signals (?).

[The Great Bear]

 

I'm building and placing the last signals on the layout - at last, only a year in the making! Is there any particular distance 2 should be away from 3 & 9 - I don't have enough distance I think to get it far enough back to protect the longest train standing at 3, if that were a criteria.

 

Thanks

 

Jon

[The Stationmaster]

I'm building and placing the last signals on the layout - at last, only a year in the making! Is there any particular distance 2 should be away from 3 & 9 - I don't have enough distance I think to get it far enough back to protect the longest train standing at 3, if that were a criteria.

 

Thanks

 

Jon

It really depends on what the purpose of No. 2 was.  so several things to consider -

 

Firstly was it shoved towards the station because of 'Rowell Lane Crossing' preventing it being anywhere else?  If that was the case then logically it should have been at least 440 yds in rear of No.5 to be of much use for anything.

 

Secondly, and ideally, it should have been at least 440yds in rear of No.3 as that would then create a Clearing Point which would enable a train to be accepted whilst another was crossing off the branch towards the Up Line or even shunting back off the Down Line into the yard.  I would regard this as the most likely siting of the signal were it not for the presence of the level crossing and this would have been by far the most useful position for the signal.

 

However it was not unknown on the GWR for Home Signals to be less than 440yds in rear of the next signal in advance when there seemed to be no logical reason for having them that close together.  In that situation I can really regard as no more than a belt and braces situation in which over-running the Home was considered to be a better option than over-running the next signal in advance if it happened to be the Home  (unless there was a Modified Clearing Point - usually highly unlikely).

 

We (you) ought to then consider selective compression of course.  440yds is still an awful long way when scaled down to 4mm scale - it's in the next room (or the garden) in modelling terms so you either have the signal as far beyond the longest train length in rear of signal No.3 as you can imagine and take that as 440yds and operate accordingly or You assume it isn't 440yds and operate accordingly or you assume the signal is 440yds back and out of sight and operate accordingly.  (Or you put the signal where you think it looks best - never a bad idea in this sort of situation ).

[The Great Bear]

It really depends on what the purpose of No. 2 was.  so several things to consider -

 

Firstly was it shoved towards the station because of 'Rowell Lane Crossing' preventing it being anywhere else?  If that was the case then logically it should have been at least 440 yds in rear of No.5 to be of much use for anything.

 

Secondly, and ideally, it should have been at least 440yds in rear of No.3 as that would then create a Clearing Point which would enable a train to be accepted whilst another was crossing off the branch towards the Up Line or even shunting back off the Down Line into the yard.  I would regard this as the most likely siting of the signal were it not for the presence of the level crossing and this would have been by far the most useful position for the signal.

 

However it was not unknown on the GWR for Home Signals to be less than 440yds in rear of the next signal in advance when there seemed to be no logical reason for having them that close together.  In that situation I can really regard as no more than a belt and braces situation in which over-running the Home was considered to be a better option than over-running the next signal in advance if it happened to be the Home  (unless there was a Modified Clearing Point - usually highly unlikely).

 

We (you) ought to then consider selective compression of course.  440yds is still an awful long way when scaled down to 4mm scale - it's in the next room (or the garden) in modelling terms so you either have the signal as far beyond the longest train length in rear of signal No.3 as you can imagine and take that as 440yds and operate accordingly or You assume it isn't 440yds and operate accordingly or you assume the signal is 440yds back and out of sight and operate accordingly.  (Or you put the signal where you think it looks best - never a bad idea in this sort of situation ).

 

Thanks, Mike. Given that the longest train I can run/fit in the longest staging yard road as below extends right to the limit of the scenic section when stopped at 3, then it'll have to just go where I fancy it and argue it's providing protection to the crossover by signal 3, I recall something from earlier in this thread along the lines that on western ideally you had two signals protecting them. Also, the footbridge getting in the way of the view of 3 is another good reason. If I ever do try to interlock the signals, it'll make that more interesting too

 

[The Stationmaster]

About where the brakevan/rear 2-3 wagons are, and on the cutting bank on the opposite side of the line because of the curve ... 

[The Great Bear]

About where the brakevan/rear 2-3 wagons are, and on the cutting bank on the opposite side of the line because of the curve ... 

A popular place, that, as I'd drilled the hole for 39 to go there, as the photos show it a fair distance away from the platform end. But no reason why I can't move that a bit closer to the platform. I can't recall seeing two signals back to back in opposite directions in any photos - maybe you have, Mike?

 

Thanks

 

Jon

[The Stationmaster]

A popular place, that, as I'd drilled the hole for 39 to go there, as the photos show it a fair distance away from the platform end. But no reason why I can't move that a bit closer to the platform. I can't recall seeing two signals back to back in opposite directions in any photos - maybe you have, Mike?

 

Thanks

 

Jon

I've definitely seen, and seen photos of, them back to back on the same post although that wasn't too common on the Western especially - I think - on main line routes.   i would move 39 a bit nearer the platform especially in view of the curvature.