Signal box diagram - views please

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barhamd
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Signal box diagram - views please

Postby barhamd » Mon Dec 03, 2018 2:31 pm

Hi All

I've been making progress on my Stour Valley Dream, based on Clare and have drawn up a signalbox diagram based on the original on signalbox.org
https://signalbox.org/diagrams/clare1933.jpg

Because my frame is 'round the other way' I've decided to renumber the levers left to right to match the orientation of the layout and I've upgraded the arrangements at Ashen Road level crossing to include a frame to control the fictional sidings to the fictional mill! I've also decided to include on the frame the points in the yard which would have been hand-operated with local levers just to keep all the operating levers in the same place.

I've had a first quick go at the locking, this is will arranged via servos under the point levers controlled from JMRI.

clare-diagram.jpg


Open to suggestions....

David

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grovenor-2685
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Re: Signal box diagram - views please

Postby grovenor-2685 » Mon Dec 03, 2018 3:38 pm

Looking at levers 5 & 6,you have 6 released by 5. This implies that the lock lever stands normal when the points are locked, and that the points are only locked in their normal position. This is probably the less common option for lock levers but is perfectly acceptable. However having chosen that arrangement it should be consistent through the frame and hence 18 released by 19 is required.
Incidentally its not usual to state the locking as eg. 2 locked by 5, its normal to say 2 locks 5. For the releases either released by or releases can be used and some styles of table use both so that the coverse are written in. Converses are automatic in mechanical locking but need to be included specifically in electric or electronic locking.
Regards

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Mon Dec 03, 2018 4:00 pm

Thanks Keith

I'd wondered which way around the FPL would be. If it is more common for the points to normally be unlocked then I'll do it that way. Presumably the point only needs to be locked when signaled in the facing direction?

David

JFS
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Re: Signal box diagram - views please

Postby JFS » Mon Dec 03, 2018 5:04 pm

barhamd wrote:I'd wondered which way around the FPL would be.


I agree with Kieth that it is more common for the FPLs to stand "out" (ie reversed when locking the point) but companies varied in their practice so if you know what your "prototype" did you can follow that. However, from a model point of view, one thing to bear in mind is that the FPLs spend a lot of time in the "locked" position even when nothing much is happening, and means having levers reversed in the frame which presents an opportunity for them to get walked-into / snagged-on-coat-sleeves / knocked by mugs of tea etc, so I prefer to have them standing-in unless there is a good reason not to. Obviously, if your are modelling a real location you have no choice...

Just a couple of minor details....
- Is there a slip of the finger in the description of the lever 1 in the GF - did you meant "Distant" signal?
- compared with the original, you don't seem to have a signal reading out of the siding over 14 points (you need a number at both ends BTW). Perhaps this should be 13?
- you don't have a signal reading into the sidings over points 7 - there is none on John Hinson's diagram either, but I would have thought such a signal quite important - even though it complicates the locking a bit. It might therefore be that signal 15 (in your version) is intended to read over both 14 and 7 point in which case the locking would read "Released by (7 OR 14)", Locks 8, 13(?)

I have not checked the locking as it is a bit difficult to fathom written that way round! - could you re-draw it in table form as Keith suggests?

I will be doing my best to get you try mechanical locking - it is not difficult for such a simple layout and servos are a right royal PITA becuase they are far from instantaneous in their movement and by no means any less effort to fit / wire etc... :D

Good luck!

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Mon Dec 03, 2018 5:41 pm

Thanks Howard

To your points..

I've corrected the 'distance' to 'distant'. The original arrangement was apparently a drum which had signal wire leading to the slot on distant 1 and the distant arm on signal 23. It was wound with a crank handle and locally referred to a 'a mangle'. The red lights and targets on the level crossing gates counted as a stop signal.

The coal siding accessed by points 14 was very short (about 3 wagons long) and a rebuild of the arrangement shown in John's plan from about 1952-3. I couldn't see how point 14 could ever be put back normal while it was being shunted and I would not expect a locomotive to ever be 'shut in'. Given the limited number of shut signals elsewhere I suspected that there wasn't a signal to leave the siding as a locomotive would never be in front of it.

The lack of a shunt signal showing the route into the yard is, I think, explained by the position of the prototype signalbox. In reality a train about to set back into the yard would have been directly outside the box. Perhaps I should model an opening window and waving green flag?

I've tried to write the locking table in a more conventional format.

clare-diagram-v2.jpg



David

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grovenor-2685
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Re: Signal box diagram - views please

Postby grovenor-2685 » Mon Dec 03, 2018 6:22 pm

David,
You took my words to heart wrt 'locks' but ignored my mention of 'released by'
When translating locks R to released by there are one or two omissions.
I'll try and work out a table shortly.
Rgds

PS. With double line signalling where there was often a procession of trains needing no change to the routes set it was convenient to keep points locked most of the time, and with the usual arangement this resulted in levers standing reverse to some inconvenience to the bobby walking up and down the frame, hence the occasional use of locked when normal lock levers.
In a single line like yours, however, the points are changed for almost every train so no bebefit in keeping the points locked alll the time.

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Mon Dec 03, 2018 6:53 pm

so, for example
1 should be written as 'released by 2,3,4'
2 should be written as 'released by 5, locks 7'

Is that the right idea?

Thanks
David

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grovenor-2685
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Re: Signal box diagram - views please

Postby grovenor-2685 » Mon Dec 03, 2018 6:59 pm

Yes

JFS
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Re: Signal box diagram - views please

Postby JFS » Mon Dec 03, 2018 7:08 pm

barhamd wrote:The coal siding accessed by points 14 was very short (about 3 wagons long) and a rebuild of the arrangement shown in John's plan from about 1952-3. I couldn't see how point 14 could ever be put back normal while it was being shunted and I would not expect a locomotive to ever be 'shut in'. Given the limited number of shut signals elsewhere I suspected that there wasn't a signal to leave the siding as a locomotive would never be in front of it.


Ah! The local knowledge is always key...

barhamd wrote:The lack of a shunt signal showing the route into the yard is, I think, explained by the position of the prototype signalbox. In reality a train about to set back into the yard would have been directly outside the box. Perhaps I should model an opening window and waving green flag?


Well, there certainly were some railways which did not believe in shunt signals at all, and I suppose the question is - how was the layout worked? Since there are no facilities to run round the train, I assume that the practice was perhaps to leave the local goods train just inside signal 2, then work wagons off/onto the front of the train and in those circumstances, the signalman could certainly use the Green Locking Defeater out of the window (yes you will have to model it!). But alternatively, the presence of signal 7 might indicate that the train was backed into the sidings then wagons worked between the sidings using the main line as a headshunt, in which case a signal might have been a useful indication to the drivers going in and out of the sidings with cuts of wagons.

That leads to a question concerning your point 11 - is this just a headshunt (in which case, better perhaps to have the point standing the other way) or is it a "kick-back" traffic siding? If the latter, how was it worked? Did they have a horse or was it fly / pole / chain shunted? It must have been some such as there is no signalling to work the loco to the Stoke end of any wagons.

Perhaps photos have the evidence?

Best Wishes,

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Mon Dec 03, 2018 7:28 pm

The photographs I show seem to show the pick-up goods either left on mainline or shunted into the siding at the front of the yard. The other side of the diamond was only a short cattle dock and not long enough to really be used as a head-shunt. Between points 10 and 11 sat the goods shed and I suspect that pickup goods probably used the length of the train to act as 'reach wagons' to go through the shed and pickup/drop wagons in the yard beyond. Frankly I can't see how siding 11 was shunted without recourse to GER class GG or a pinch bar!

I do have documented a freight train leaving Cambridge 'for Clare' which implies that on occasions a train may have been run around and send back the way it came.

I obviously need to make the diagram clearer, my intention was that point 7 operated the far end of the double slip as well as the connection to the yard and the shunting signal was lever 8.

Thanks for all the input.

David

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Mon Dec 03, 2018 7:56 pm

And a revised diagram..

clare-diagram-v3.jpg


David

JFS
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Re: Signal box diagram - views please

Postby JFS » Mon Dec 03, 2018 8:00 pm

barhamd wrote:I do have documented a freight train leaving Cambridge 'for Clare' which implies that on occasions a train may have been run around and send back the way it came.


As a Lancashire Lad, I'm not too sure which end is Cambridge... :? but of course a loco CAN run round (from either direction), using the main arms and a bit of Shunt into Forward Section / Blocking Back, but what it cannot then do, is get back to the same end it arrived on. So it would make sense if the train arrived from the Stoke end, did its work, ran round then departed back to Stoke - assuming that the brake van was put in the yard off the back first, then worked out last to be dropped on the back of the departing train just before the loco ran round. Though it would then need flagging out as there is no backing signal.

Of course, working your mill siding would mean leaving the train out on the main line with only the staff for protection - but then this is the Land of the Carrot Crunchers ... Oops, I mean - out in the sticks ... Sorry - Countryside. So zero risk there.

One of the trickier bits of modelling rural stations is that a lot of work was done using things like pinch bars / horses / poles / chains and they are not easy to model!

barhamd wrote:I obviously need to make the diagram clearer, my intention was that point 7 operated the far end of the double slip as well as the connection to the yard


Don't beat yourself up - just because clowns like me mis-read it does not mean it is not clear :D

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Noel
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Re: Signal box diagram - views please

Postby Noel » Mon Dec 03, 2018 10:37 pm

A few random thoughts:

If the g/f is released by Annetts key, that lets the goods train guard shunt the mill siding, but causes problems for everyone else, since the g/f cannot be unlocked except by train crews, which means that the level crossing cannot be opened until the train gets to it... Which also means that the signalman has to clear 24 with the crossing not clear and that the distant below 24 is not needed and distant 1 should be fixed, as the crossing will always be against the train. Or have I missed something? I would suggest that the g/f would be operated by a member of the station staff and released from the box. It would then be opened before a train from Stoke is accepted.

Following on from the above, signal 2 is really the wrong side of the crossing. I suggest it should be on the approach side and slotted from the g/f. (presumably, in reality the crossing was further away from the station and operated by a crossing keeper?)

All shunting of the mill siding will obstruct the crossing, which is therefore going to spend some time across the road. This is not likely to be popular (which is not to say it never happened).
Noel

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Tue Dec 04, 2018 12:06 am

Hi Noel

In reality the level crossing was about 1/4 mile away from the river bridge. This meant that the gate keeper would have had a lever which locked the gates and 'the mangle' which pulled the slot off on the distant signal coming from Stoke and also on the distant arm on the Stoke bound starter (also slotted). My intention is that these operations remain unchanged. The signalman at Clare was quite able to pull of the starter before the gates had been closed, the driver would see from the distant signal for the gates whether or not they were cleared and would expect to have to stop at the next signal (the red light on the gates) unless the distant was clear. Although in pure distance terms in my model world you are right that the home signal would probably have been the other side of the crossing with the river bridge and some trees as a bit of a scenic break it makes sense to leave it in the same position it had relative to the crossing on the prototype.

The Annett's key was only intended to allow shunting of the mill siding, so I had envisioned it locking the FPL on the ground frame. Once unlocked with the key from the train staff the goods could be shunted into the mill yard. Again in reality, had a siding been put in at this point the chances are there would have been two frames, one for the siding arrangement and a separate arrangement for the crossing keeper.

Blocking the road while shunting isn't a problem, cars would have been few and far between in that part of darkest Suffolk.

David

John Palmer
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Re: Signal box diagram - views please

Postby John Palmer » Tue Dec 04, 2018 12:37 pm

David, I expect you are probably already aware of the excellent picture of Ashen Road crossing at http://www.stourline.co.uk/page47.htm (Picture no.36, and in colour, no less!), showing an enlarged target performing the function of 'gate home' signal.

I'll stick my head above the parapet with the diagram below, which sets out my take on the required locking. Those with a better grasp of the principles than I can shoot holes in it as they see fit.
Clare Signal Box Diagram.jpg
I quite understand your desire to concentrate controls for points in a single frame, but assume you recognise that in practice putting 10 and 11 points under the signalman's control would be highly inconvenient because his view of the yard where those points are located would be obstructed by the station building. Might it be worth considering including their controls in the frame, but excluding them from the numbering sequence – and perhaps putting their lever quadrants a short distance from the others?

I'm not clear about your intentions as regards the control of the double slip, as the diagram suggests a different arrangement from that on the prototype, in which the switch immediately adjacent to the number 9 on your diagram was ground worked, whilst the other switch at that end of the slip was controlled from the box (i.e. the switch controlling a movement either into the goods shed or its adjacent road from the running line). Perhaps it's your intention instead to gang these switches together, as in the case of the switches controlled by 7. But if not, then the switch leading from the dock road (to the right of the slip) will need a lever to control it independently, and if you are concentrating switches into the one frame then a place must be found in it for this lever, as for 10 and 11.

Either way, there remains a slight problem in that signal 8 reads over approaches to the double slip both from the goods shed and from the road adjacent to it. Potentially this may make it possible to clear 8 for a movement that will burst one of the switches at the other end of the slip.

I haven't changed the numbering of levers controlling the slip and its adjacent ground signal, but there's an opportunity here to eliminate the awkward 'pull between' sequence for the signalman of 7 then 9 then 8.

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Noel
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Re: Signal box diagram - views please

Postby Noel » Tue Dec 04, 2018 2:30 pm

barhamd wrote:In reality the level crossing was about 1/4 mile away from the river bridge


Which in 4mm terms means about 17ft. I don't know how much space you have available, but given the usual sort of available space, I assume the crossing to be much closer to the station, and possibly even within station limits. If that is so, it would probably have been dealt with, in signalling terms, very differently (also possibly, but not necessarily, true for the siding connection). Selective compression is usually necessary in model railways, but with major compression of this sort it can be difficult to make the prototype signalling look convincing.
Noel

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Tue Dec 04, 2018 6:22 pm

Hi John

I'd seen the picture you mentioned, the large target on the gates is wonderful.

Ultimately this is all a compromise and I'm pretty happy that I'm now getting close to something which I can live with. I'm not going to be able to extend the room by another 17 feet just to get more space for the home signal!

The double slip is a bit of a problem, in model form I've joined the tie-bars together as is conventional so I'm not going to separate them now. Again if I was going to have the levers for the yard separate from the frame it might make more sense. The ground disk did allow a train to exit the yard from either line. I think swapping over levers 8 and 9 might help avoid the nasty pull of 8 between 7 and 9.

Having levers 10 and 11 on the main frame is a convenience for the model. My signalman has a helicopter eye view..

Thanks

David

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grovenor-2685
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Re: Signal box diagram - views please

Postby grovenor-2685 » Tue Dec 04, 2018 8:32 pm

Only just managed to get back on line following a computer problem that hit when I had almost finished the locking table last night. Wiped out that work as well as the web access.
Anyway while off line I did manage to redo the table so here it is.
locking table.pdf
(23.11 KiB) Downloaded 29 times

locking table.ods
(53.55 KiB) Downloaded 13 times

There are a couple of differences between this and John's above. The main one being the method of preventing simultaneous entry. I used 24 rel by 6 to achieve this. John has used 2 locks 19 and 24 locks 5. On balance I prefer John's method so use that.

If it were me I would not want to spend time and money building spare levers. Why not use the spares for the siding hand points? Pull betweens and the signalman's view are not an issue for the model as Dave says.
Regards

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barhamd
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Re: Signal box diagram - views please

Postby barhamd » Tue Dec 04, 2018 11:44 pm

Thanks for that Keith, very useful.

Now, I can think about painting the lever frame to avoid concentrating on building the fiddle yard!

David

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grovenor-2685
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Re: Signal box diagram - views please

Postby grovenor-2685 » Wed Dec 12, 2018 1:24 pm

I have managd to re-install JMRI and have set up a simulation for your frame using only ADD conditions as would be the case if using CANCOND firmware.
All appears to be OK, so far as I can see the locking works as required.
Clare frame for JMRI.zip
(4.27 KiB) Downloaded 11 times

It uses JMRI 4.12, if the panel does not come up properly there could be a discrepancy with the paths to the icons from older JMRI versions.
Regards


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