Ground Signals

Discuss the prototype and how to model it.
colinglenister
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Ground Signals

Postby colinglenister » Tue Mar 17, 2020 8:51 pm

Attached is the track plan of my proposed layout. Can anyone advise me what, if anything, should be installed at the pisition of the question mark.

Movement from the yard to the runaround across the single slip is planned.

any comments on the signalling would be appreciated too.

Thanks Colin
20200317_204410.jpg
Track plan

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Neil Smith
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Re: Ground Signals

Postby Neil Smith » Tue Mar 17, 2020 9:33 pm

colinglenister wrote:Attached is the track plan of my proposed layout. Can anyone advise me what, if anything, should be installed at the pisition of the question mark.

Movement from the yard to the runaround across the single slip is planned.

any comments on the signalling would be appreciated too.

Thanks Colin


Hi Colin

It depends if you want to signal from the sidings to the platform as well, in which case two ground signals one above the other (one for each route, with the top one being the left hand option ie to the run round) . I would suggest that as the only way to run a lock round is by having onto the yard, then yes you do want this option. If in the unlikely event you don't wish to signal into the platform then just one doll ie ground signal will be enough. I am not sure how prototypical it is to run round into the yard like this but I guess it does protect the level crossing, were space to be an issue.

A few other thoughts on the signalling:
You need a trap point to stop runaways coming onto the mainline, between these ground signals and the single slip.
Normal practice would be for the signals to be at each end of the frame with the points in the middle, so you would probably want to renumber the starter, assuming that the signal alongside the bay /duck is for the running line?
Depending on how long your platform is, and where the signal box is located, the rodding run for the release point in the run round may be too far away to be operated from the box (in which case a solution would be to have a lever in the box to release a ground frame down there).
That release point probably needs to have a lock on it, and certainly the mainline side of the slip must be locked assuming passenger services run out of the platform.
Finally yard points are most likely hand operated not controlled by the box.

How this helps. Greater minds than mine on here will probably proffer more wisdom!

All the best

Neil

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Noel
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Re: Ground Signals

Postby Noel » Tue Mar 17, 2020 10:31 pm

This seems to be a pretty unusual layout, for a number of reasons. The first is that the l/c implies a road that was there before the railway, which is fair enough, but I would have expected the line's Act to have extinguished it in favour of a road round the end of the line, to the station itself and so onwards. A l/c built later that close to a terminal station is not really credible, in my view.

Second is that run round only being possible via the yard is unlikely; connections between yard and loop across the main were not uncommon, but the connection at the end of the loop would normally be separate, so far as I know. Alternatively, you could keep the slip, but turn it round.

The third is that the yard points would normally all be on hand levers, the only ones operated by the box [which you have not shown, incidentally] would be 3, 4 and 7 (if I've read your diagram correctly), the last to provide protection for the main line, plus the one at the end of the loop.

Fourthly is that the layout as shown means that the first train has to be shut into the yard before a second can be accepted. In reality the daily freight could run in a gap between passenger trains, and the station layout implies only one passenger train is present at a time. There doesn't seem to be any real need for a box and signals at all [and it has to be both or neither]; the line could be worked "one engine in steam" from the last crossing point, with a ground frame for the points.

Sorry to be a bit negative; if you can explain why you adopted the approach you have, and what sort of services you expect to operate, we may be able to explore alternatives.
Regards
Noel

colinglenister
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Re: Ground Signals

Postby colinglenister » Tue Mar 17, 2020 11:46 pm

Thanks for all your comments and advice. I realise I left out some important details:

Amendments in red:

Ground frame in the yard
Position of signal cabin
Replace single slip with double slip
Add facing point locks to toes of double slip on running line

Platform is a scale 355ft

How does that change things?

Operationally I want LC for interlocking exercise.

A canal limits railway site on south side on the model

Cheers Colin
20200317_233137.jpg

Phil O
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Re: Ground Signals

Postby Phil O » Wed Mar 18, 2020 8:21 am

Sidings are usually worked by hand levers, operated by the shunter. Interlocked points and signals were normally reserved for passenger carrying lines and lines attaching to passenger carrying lines, plus associated signals to protect the passenger lines.

Cheers

Phil

colinglenister
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Re: Ground Signals

Postby colinglenister » Wed Mar 18, 2020 8:51 am

Forgot to amend the inset
20200318_085020.jpg

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Noel
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Re: Ground Signals

Postby Noel » Wed Mar 18, 2020 10:12 am

A double slip is maintenance heavy [which is one reason why the modern railway doesn't like them much] and would usually be avoided in a country branch terminus, which was rarely short of room. However, it's not impossible; it does however introduce a further problem or two.

If you intend to regularly run trains direct to the loop, then your home will have to have a bracket signal to authorise that. Otherwise, for very occasional use, it could be authorised directly by the signalman by hand signal or flag, after the train has been stopped at the home. You also need a loop starter, or a ground signal, plus an advanced starter, although this could be "offscene" on the model. Also needed are traps at both ends of the loop to prevent anything on the loop interfering with the main running line; the platform line may need an fpl on the escape crossover.

The ground frame in the yard is unnecessary; these points would have been operated by hand levers adjacent to the point, as no form of interlocking is needed. However, depending on the distance from the box the escape crossover at the far end of the loop might need to be operated by a ground frame, and this would have to be locked from the box. There were practical limits on the length of rodding run a signalman could operate, and rules on distances from pointwork to the box imposed by the BoT. These distances were extended over time, but older set-ups were not always altered. If the crossover is operated directly from the box, then ground signals are needed.
Regards
Noel

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Neil Smith
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Re: Ground Signals

Postby Neil Smith » Wed Mar 18, 2020 11:08 am

I would agree with Noel's thoughts, but would add that an advanced starter would need to protect the LC so that any loco running round would not then foul the crossing (that or you would need the crossing to be interlocked so that the run round could only take place when the gates were open to the railway which may not be attractive if the road were busy). Further you would then need a ground signal to allow the engine to come back onto the train. And unless your line is "one engine in steam" consideration needs to be given to ensure that an engine running round which wrongly passes the advanced starter could still stop before colliding with a second incoming train held at the home signal.
And I don't have a precise measurement but one example of a terminus with a release point (and lock) ground frame released by the signal box is Lakeside here in Cumbria, where the box is (rough measurement from the NLS old maps) something just over 200m away from the GF. Your platform length might just squeeze in to allow control from the box, but then as Noel says you would need ground signals down there.
Finally, your numbering doesn't allow for an out of view distant signal. There was some discussion on here elsewhere previously about the fact that although more modern practice would be to have a fixed distant approaching a terminus, that in actual fact operating distants for terminii were the order of the day in Victorian installations, and lingered on well into the 20th century. So depending on when your line was built, the lever number 1 in the box perhaps should be the distant reflecting the status of the home signal.
Hope this all helps!
All the best
Neil

Armchair Modeller
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Re: Ground Signals

Postby Armchair Modeller » Wed Mar 18, 2020 11:15 am

Somehow reminds me of Cromer Beach station (mirror image). I can only find this signal diagram on the Web at present. I am sure there was an earlier one at one time showing lots of goods sidings. Obviously this is complicated by the 2 separate running lines, but an earlier diagram might give some inspiration

From RMWeb

Image

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Noel
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Re: Ground Signals

Postby Noel » Wed Mar 18, 2020 12:17 pm

Neil Smith wrote:And unless your line is "one engine in steam" consideration needs to be given to ensure that an engine running round which wrongly passes the advanced starter could still stop before colliding with a second incoming train held at the home signal.


Not an issue, for two reasons. First, a driver was expected to observe and obey signals, so shouldn't pass the advanced starter unless it is clear. Secondly, any such movements would be highly illegal. The signalman must have 440 yards clear beyond the home signal [known as the clearing point] before accepting a train. Here that would mean clear to the buffers. He must also not foul the clearing point until the train has arrived. This requires the l/c to be opened to the railway before the train can be accepted [which is why the position of the l/c is a problem] and a token/tablet/electric staff issued; it also requires the line to the clearing point to be clear and to stay clear, so there cannot be a train in the platform to be run round. If there was, a goods train could be accepted into the loop if that was clear, but a loco running round rules that possibility out as well. Any shunting onto or across the running line would also be ruled out.

Neil Smith wrote:an advanced starter would need to protect the LC so that any loco running round would not then foul the crossing


The starters will protect the crossing if it is close to the station, with the advanced starter beyond it [technically the crossing has its own stop signal, the red disc or diamond and the red lamps on the gates]. However, if the crossing is close to the station, the potential problem is a driver who, for whatever reason [carelessness, slippery rails, total brake failure, etc.], fails to stop in time and goes through the gates. For this reason, if the gates are close to the run round they would normally be opened, to stop road traffic for safety, bearing in mind that the precision we can apply to models does not apply to a real locomotive, so it needs several times its own length available even if all goes OK. If the gates are some distance away this is less of an issue.
Regards
Noel

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Neil Smith
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Re: Ground Signals

Postby Neil Smith » Wed Mar 18, 2020 1:26 pm

Noel wrote:
Neil Smith wrote:And unless your line is "one engine in steam" consideration needs to be given to ensure that an engine running round which wrongly passes the advanced starter could still stop before colliding with a second incoming train held at the home signal.


Not an issue, for two reasons. First, a driver was expected to observe and obey signals, so shouldn't pass the advanced starter unless it is clear. Secondly, any such movements would be highly illegal. The signalman must have 440 yards clear beyond the home signal [known as the clearing point] before accepting a train. Here that would mean clear to the buffers. He must also not foul the clearing point until the train has arrived. This requires the l/c to be opened to the railway before the train can be accepted [which is why the position of the l/c is a problem] and a token/tablet/electric staff issued; it also requires the line to the clearing point to be clear and to stay clear, so there cannot be a train in the platform to be run round. If there was, a goods train could be accepted into the loop if that was clear, but a loco running round rules that possibility out as well. Any shunting onto or across the running line would also be ruled out.

Neil Smith wrote:an advanced starter would need to protect the LC so that any loco running round would not then foul the crossing


The starters will protect the crossing if it is close to the station, with the advanced starter beyond it [technically the crossing has its own stop signal, the red disc or diamond and the red lamps on the gates]. However, if the crossing is close to the station, the potential problem is a driver who, for whatever reason [carelessness, slippery rails, total brake failure, etc.], fails to stop in time and goes through the gates. For this reason, if the gates are close to the run round they would normally be opened, to stop road traffic for safety, bearing in mind that the precision we can apply to models does not apply to a real locomotive, so it needs several times its own length available even if all goes OK. If the gates are some distance away this is less of an issue.


I had a feeling Noel you would be spotting the muddled holes in my thinking - again! Thank you... And I had forgotten about the red disc on the gates being a signal.. doh..

Regarding the first paragraph, would I be right in thinking that posting an outer home sufficiently far out that the LC falls beyond the clearing point would solve the issue you raise about having to have the crossing closed to the road for all the time the incoming train takes to cover the section?

Clearly this might mean it is off the scenic section, but I am thinking of the line a a whole rather than just the modelled section. Also - yes, having a a second line to receive incoming trains (e.g. a second platform/a direct run into the goods yard, or at least signalled into the run round loop knowing the loco on the first train must have run round first would be helpful too.

All the best

Neil

colinglenister
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Re: Ground Signals

Postby colinglenister » Thu Mar 19, 2020 11:07 am

Maybe I should redesign the station throat/runaround such that entry to the goods yard is off the running line before the run around? But then how do I get to run around wagons without using the platform run around.
Layout is 9ft x 2ft

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Noel
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Re: Ground Signals

Postby Noel » Thu Mar 19, 2020 12:29 pm

Neil Smith wrote:Regarding the first paragraph, would I be right in thinking that posting an outer home sufficiently far out that the LC falls beyond the clearing point would solve the issue you raise about having to have the crossing closed to the road for all the time the incoming train takes to cover the section?


In theory, but it is yet further complexity in a situation where the railway would be trying to avoid it; there would probably not be much road traffic anyway, and little of what the was in any great hurry. There is also the question of how does the signalman know that the train is there if he can't see it because it's round a bend? The 440 yards minimum from signal to clearing point would still apply. A track circuit is not possible as they were not invented until 1872, and the BoT was still fighting to get main line companies to use them in busy locations 40 years later.

As I suggested earlier, much of this is an artificial discussion, because the simple answer, and most likely to be used, is to put a clause in the line's enabling Act to divert the road around the end of the line. If it was a parish road nobody would be likely to object, as anyone with pretensions would have had horse drawn transport, and the others would just walk; in either case an extra 200 yards or so would not be seen as presenting a problem, especially since most locals would probably be in favour of the line. The station might well be over a mile away from the nearest settlement anyway. If it was a Turnpike there might be an objection from the Trust, but probably nothing unsurmountable. If the locals could make a good case for it the railway company might put in a foot crossing, which has no block implications.

The way we think has been changed irrevocably by the internal combustion engine; as a child in the early 1950s I lived in a very small hamlet in the wilds of north Dorset. There was no bus service [except the school bus I used to go to primary school, which carried only school children], and we had no car, so my father walked over 1.25 miles each way to the nearest railway station to commute to work, and to reach his allotment in the nearest town, as did my mother at least once a week to go shopping, and, of course, I went too during school holidays. It sounds strange now, but in Victorian times it would have been perfectly normal, although without the school bus, of course.
Regards
Noel

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Noel
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Re: Ground Signals

Postby Noel » Thu Mar 19, 2020 12:54 pm

colinglenister wrote:Maybe I should redesign the station throat/runaround such that entry to the goods yard is off the running line before the run around? But then how do I get to run around wagons without using the platform run around.


I can't answer that as it depends on what you want to achieve; all I, and anyone else, can do is point out what the railway's rules required. I do think that the question may actually start from an incorrect assumption, though. You can take the goods yard access from the platform line, from the loop or from the running line at any point short of the station, and with access facing the station [uncommon] or the junction, or even both if there is a private siding, for example. Any of these is possible, but all have implications for the way the rules are applied, which may not be the same in every case.

If you need to come out onto the running line to access the loop, that is quite possible. The one constant is that you cannot accept a train if the line to the clearing point is a) not entirely clear and protected against all conflicting moves, and b) will stay that way until the train arrives. The converse also applies, if a train has been accepted, you cannot access the running line until that train has arrived. Shunting into the section behind a departing train is legal until you get 'out of section' from the next box; after that you either have to clear the line or tell them that the line is blocked.

As I commented to Neil, railways would generally try and make things no more complex than was necessary to achieve the operating results that they wanted [although you do wonder when you see some locations...]
Regards
Noel

John Palmer
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Re: Ground Signals

Postby John Palmer » Thu Mar 19, 2020 2:56 pm

May be worth noting for the purpose of these discussions that a level crossing does not count as an obstruction within the clearing point.

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Will L
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Re: Ground Signals

Postby Will L » Thu Mar 19, 2020 4:10 pm

Noel wrote:A double slip is maintenance heavy [which is one reason why the modern railway doesn't like them much] and would usually be avoided in a country branch terminus, which was rarely short of room. However, it's not impossible; it does however introduce a further problem or two...


Depends a bit on the company that built it. The GER was notably not scared of complex point work. They even had a design for a small wayside halt that turns up quite often and consists of a point and a double slip .

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Noel
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Re: Ground Signals

Postby Noel » Thu Mar 19, 2020 4:15 pm

John Palmer wrote:May be worth noting for the purpose of these discussions that a level crossing does not count as an obstruction within the clearing point.


Yes, apologies John, I got that bit wrong. Hopefully everything else is right :evil:. BR Rule 99 [which has a long ancestry] required crossing gates to be closed across the road unless opened to permit something to cross; with the gates closed the signalman would usually clear the home signal for the approaching train, locking the gates until the train has arrived.
Regards
Noel

colinglenister
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Re: Ground Signals

Postby colinglenister » Tue Mar 24, 2020 4:39 pm

Thanks for all the info. I think I understand most of it.
I want to have more than one engine in steam, hence signals etc because I am also interested in interlocking.
As you can see from the attached (new) design, the location is bounded to the south by a canal (I want water too), hence the road cannot be rerouted as the cost is assumed to be prohibitive.

Will the new track plan work within the rules do you think?
20200324_154401.jpg

davebradwell
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Re: Ground Signals

Postby davebradwell » Tue Mar 24, 2020 5:37 pm

I think this plan is ultimately doomed, Colin. You've 2 nice sidings there but you can't put anything in them without clearing out the goods yard first. The curve in there looks about 12" radius, too. Why not make it look like a through station and put the crossing at the other end - I think you'll still have to open the gates when a train arrives or loco runs round. Then you can sort out the yard design with B6 or larger points to avoid issues with buffer locking and coupling length. I feel it needs more justification for the second engine, too.

Sorry!

DaveB

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Noel
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Re: Ground Signals

Postby Noel » Tue Mar 24, 2020 8:30 pm

There is a further issue with the length of the layout as well. You indicated that the length, presumably of the visible area only, is 9ft. As a rule of thumb, a B6 point is about 12 ins long; A5s are shorter, but a have a sharper curve which has its own drawbacks. Buffer stops are about 2.5 - 3ins each. The length for a loco at the end of the loop will vary according to the length of the largest loco you want to run, but, including buffers, will probably be a minimum of about a foot. Add the length of five points to this, and deduct from 9ft. How long are your loop and the sidings going to be?
Regards
Noel

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grovenor-2685
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Re: Ground Signals

Postby grovenor-2685 » Tue Mar 24, 2020 8:44 pm

Also the double disc and CP shown on the signal plan cannot be physically fitted on the track plan, you need to use the first yard point as the trap and have yellow discs. The radius of the entry to the sidings looks very tight as well it will be very restrictive on stock.
I would suggest you download Templot and try using that.
Regards
Keith
Grovenor Sidings

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Noel
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Re: Ground Signals

Postby Noel » Tue Mar 24, 2020 9:15 pm

grovenor-2685 wrote:you need to use the first yard point as the trap and have yellow discs.


Not disagreeing with the principle of what Keith has said, but it depends on what period you are modelling [which we don't know]. Assuming no significant alterations to the layout since Victorian times, likely in a country terminus, conditional discs would not have been yellow [a 20th century variation basically] but red on a white disc, as usual, but with white lights instead of red, probably not very obvious in 4mm. The earlier rotating signals had the same variation when conditional.
Regards
Noel


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