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Drawing signaling diagrams

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Drawing signaling diagrams

Unread postby Mitchell285 » Fri Nov 30, 2012 11:56 am

Hi all,

Quick question , possible quite ovbious when i look into it more but when a new box was commitioned how was the numbering done for the levers?

is it very much a case of left to right 1 , 2 ,3 or is there a more techincal way of numbering signals and points ?

I only ask as i want to make a decent diagram for my model railway but thought if im doing it , i should do it properly .

Thank you all
Mitch
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Re: Drawing signaling diagrams

Unread postby Peter Jordan » Fri Nov 30, 2012 1:24 pm

Practice varied over the years and from one railway/region to another. To give you a more definitive answer we would need to know what railway company your model is based on, and at what period in time it is set.

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Re: Drawing signaling diagrams

Unread postby MRFS » Fri Nov 30, 2012 1:46 pm

Peter's right: just to put a little more flesh on the bones: it depends on all sorts of variables - the levers could be numbered geographically with the points in the middle of the frame or the points could be on the outer ends of the frame with the signals in the middle.
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Re: Drawing signaling diagrams

Unread postby Mitchell285 » Fri Nov 30, 2012 3:45 pm

its a heritage line really , but if I was to give it an area and era , id say Great Western on a branch line somewhere close to penzance 1930's ish.

I hadnt relised the frames differed from regions , id bave thought it be a near standard thing , learn something new everyday .

cheers
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Re: Drawing signaling diagrams

Unread postby Sharpey » Fri Nov 30, 2012 4:50 pm

Mitchell285 wrote:I hadnt relised the frames differed from regions , id bave thought it be a near standard thing , learn something new everyday .

cheers

It is surprising how much is "standard" in railway signalling, unfortunately everyone seemed to have their own standard!

A basic logic that I was taught when I started on the S&T many moons ago was this -
"Everything is standard.......... except for that which isn't !! And when it is standard you just have to work out which standard it is to"

Not exceptionally helpful, but it does sort of sum it up. :?

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Re: Drawing signaling diagrams

Unread postby JRB » Fri Nov 30, 2012 5:06 pm

And remeber to avoid "pull-betweens". If a regular movement requires pulling a lever between two others already reversed, the signalman will (rightly) curse. Otherwise, the most used routes should as far as practicable require consecutive levers to be puled in order R-L or L-R. There are many other considerations required. The best policy for a model is to find a prototype and follow it as far as possible.
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Re: Drawing signaling diagrams

Unread postby Peter Jordan » Fri Nov 30, 2012 6:30 pm

Hmm.......I know of at least one instance where the retrospective (and in my view totally unnecessary) addition of sequential locking actually introduced 'pull betweens' where none had existed before.

However, as mentioning the name of the railway where this was done is likely to prove (Highley)embarrassing, I will refrain from doing it.

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Re: Drawing signaling diagrams

Unread postby Chris Osment » Fri Nov 30, 2012 7:23 pm

Perhaps the best answer might be for John H to kindly move this thread to the 'Model' forum and the originator to post a sketch of his proposed layout and signalling, then we might be able to suggest a likely solution for him?
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Re: Drawing signaling diagrams

Unread postby John Hinson » Fri Nov 30, 2012 7:52 pm

Chris Osment wrote:Perhaps the best answer might be for John H to kindly move this thread to the 'Model' forum and the originator to post a sketch of his proposed layout and signalling, then we might be able to suggest a likely solution for him?

Agreed! A sketch of the proposed layout is the best way to go.

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Re: Drawing signaling diagrams

Unread postby Mitchell285 » Sat Dec 1, 2012 7:45 am

thank you , will do one tonight when im home from work
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Re: Drawing signaling diagrams

Unread postby Mitchell285 » Mon Dec 3, 2012 6:09 pm

You've all been really helpful guys and girls!

i know that things like distances and 1 or 2 signals are in the slightly wrong place but that’s due to operational limits and also because i feel that for the size and ideas behind it ( being a heritage line , there’s things done by dummys and hand signals which I believe would be done via semaphores in real life)

Anyways, I wasn’t sure of the rules about photo size, so thumb pics with full size links.

Lamorna Box is just a basic end of branch line terminus
Image

Stockley Box is the main area of the line, although I realise points in a yard would be controlled via a ground frame and not the box, as its only be operating the whole line, points will be controlled via the box in this case

Image

Thank you
Mitch
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Re: Drawing signaling diagrams

Unread postby dave55uk » Mon Dec 3, 2012 6:55 pm

Two things jump out at me of Stockley, both concerning the loop adjacent to the platform.
In the L->R direction, you have a dolly signalling a train in, but nothing to signal it out the other end. Another dolly perhaps?

And then the dolly in the opposite direction. It would be before the trap point (if the angle of your line is meant to be that - or if not, why not? :-))
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Re: Drawing signaling diagrams

Unread postby Mitchell285 » Mon Dec 3, 2012 7:02 pm

hmm , I do hate your logic :P , but yes , your defo correct . however , there isnt a trap point due to the fact that there isnt a trap point lol! . its actully a track laying fault , when laying all tge track , it never occured to me to use trap points
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Re: Drawing signaling diagrams

Unread postby kbarber » Tue Dec 4, 2012 10:24 am

When you say "heritage line really" I'm not quite sure whether you're saying it's a model of the 1930s situation or whether it's a model of a "heritage" (what we used to call preserved) railway attempting to recreate the 1930s. if the latter, you would probably expect some more modern standards to be used in deciding what signals to have or where they should be.

If you want a diagram that looks right, it'd be no bad idea to add the trap points... if you don't get an excuse to add them to the model sometime, some rails (old point blades?) in the right place might at least give a visual impression that would help. Stockley would also need a set of traps at the right hand end of the loop, of course, but trapping can just as well be achieved by using a crossover with the "trap" route as a headshunt (of whatever length you like). As the traps would most often be worked by the same lever as the corresponding turnout, there would be no problem with extra levers and complicated numbering on the diagram.

The other thing not shown in your diagrams is facing point locks. If you assume the preservation bods track circuited everything, they would only need the actual bolt apparatus modelled (in the 4-foot between the moving point blades). If an older "feel" was being created there would also be the fouling bars stretching along the inside of one rail back from the toe of the points. If you don't want to model that, you can assume they're on the rail nearest the viewer, but it does make a difference to the rodding run. In the 1930s TCs were considered expensive and they were a bit of a rarity on branch lines (and surprisingly few on some rather more important lines too).

But the main point here is that - with a few exceptions - each FPL would need a separate lever. The Midland Railway was definitely one of the exceptions, making great use of "economical" FPLs (lock, bar and points all worked by the one lever, which should be coloured blue over black), but the GW went with the majority and tended to use separate FPL levers. Point motors have a built-in FPL so if the LH end of Stockley loop were considered too far away for manual working, you'd have a blue-over-black lever with a shortened handle for them. (In that case, that end of the layout would certainly be track circuited. Motor points without TCs were rare. There was only one place I knew that had them - Willesden Brent Sidings from early 1983 onwards - and they proved uncomfortably vulnerable to being moved under a train. That, of course, was goods lines, on which you can get away with quite a lot. The Inspectorate wouldn't allow it on a passenger line.) You probably wouldn't get motors on a branch line in the '30s, unless there had previously been another box at the LH end which was then abolished.

The signalling at Lamorna might want enhancing too. Modern standards on a preserved line would probably require a signal fixed at danger near the buffer stops end of the platform, clear of the fouling point of the run-round crossover. There would be a shunt disc or small arm beneath it to signal the loco past after hooking off but carriages conveying passengers would not be permitted past the signal. (The alternative would be to fit the Xover points with an FPL - platform line only, the loop is considered non-passenger - and to have a disc for the arriving train. A moot point whether, in the locking, that disc should be considered a "facing shunt" that must be cleared before the home can be cleared or whether it acts as the stop signal in normal circumstances, only being cleared for an arriving train when there's a long train & turnover engine.) The 1930s situation would undoubtedly have had a ground frame working the engine release crossover and no signals at all at that end of the layout.

At Stockley, in a preservation-era model it would be most usual to have an advanced starter at the left hand end. It would also be usual, at a location where shunting is likely to be common, to have outer homes (preferably far enough out that the advanced starter in the opposite direction is the clearing point). Outer homes probably wouldn't be provided in the 1930s and possibly not advanced starters either.

That probably complicates things rather than clarifies, I'm afraid. But maybe you can have some fun doodling in spare minutes over lunch (and have a browse through the signalling diagrams on the main site, to see how 'twas really done). And remember there were exceptions and peculiarities that might get you out of trouble. If you look at the lever numbering of St Albans South (1970s layout) it shows what a frame could end up looking like if alterations over the years led to levers becoming spare then being re-used for other functions - the down line signals are arranged pretty conventionally but the up lines are all over the place. All you need is a convincing story!
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Re: Drawing signaling diagrams

Unread postby lemmo » Sun Dec 9, 2012 5:48 am

A slightly different tack but same discussion: can anyone recommend PC software for creating signalling/track diagrams? cheers :)
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