Interpreting a S-R-S signal box diagram (Helston)

[Andy Keane]

I really like that photo. Hopefully the more colourful ones make sense to somebody?

Andy

[The Stationmaster]

14 hours ago, Michael Hodgson said:

See the thread above.  Whilst not applicable to a place like Helston, I believe practice in GWR days included additional colour conventions for signal levers to distinguish signals applicable to goods/slow/relief lines.

Yes, but the use of black on the lower half of  red levers for Goods etc lines seems not to have been anything like consistent

[RailWest]

14 hours ago, Andy Keane said:

I really like that photo. Hopefully the more colourful ones make sense to somebody?

Andy

At the risk of going off-topic for Helston...

 

Yellow = Distant (was usually Green in older days when Distant arms were red)

Blue/Black = FPL and Point worked from same lever

White/Brown = white levers were spares. It was a convention in some places to paint the top half white, but leave the bottom half the original colour to indicate its original function, especially if the locking had not been removed so the lever still needed to be used occasionally. Given that it is a short-handled lever, indicating (usually) that it worked something electrically, it is /possible/ that it had once been a GF release or similar and hence Blue/Brown

White/Black Chevrons = detonator placers, pointing up or down for Up or Down lines

4" White Band on lever = released from another box. (Although in BR days you might see such things on (advanced) starting signals on single-lines, where the lever was released by 'token out', AFAIK the GWR never bothered with that so you would be unlikely to have it in Helston in the 1930s.)

[The Stationmaster]

14 hours ago, Andy Keane said:

I really like that photo. Hopefully the more colourful ones make sense to somebody?

Andy

The black chevrons on a white lever (those are not painted quite like the Western way) are detonator placer levers.  The chevrons point upwards for Up Line dets and dowwards for Down line dets.

 

There were no detonator placer levers at Helston - it had only, as already noted by 'Railwest',  red (signal), black (point), and blue (facing point lock) levers.

 

The photo below shows a Reading design 5 bar vertical tappet interlocking lever frame  of the type installed at Helston in 1958.  The lever with brown and white horizontal stripes is a King Lever which allows the lever frame to be switched out of use with signals cleared for opposing directions on the single line it controls.  above the lever frame is teh block ashelf (suspended from the roof in the standard GWR manner and above it is the diagram.  The block shelf has various electric release plungers on the front (the things with brass knobs) and above them signal repeaters  (red & white for stop signals, wholly white for slots on something worked by another signal box or ground frame.  there are block bells and signal lamp repeaters mounted on top of  the shelf.

 

[Andy Keane]

6 hours ago, The Stationmaster said:

The black chevrons on a white lever (those are not painted quite like the Western way) are detonator placer levers.  The chevrons point upwards for Up Line dets and dowwards for Down line dets.

 

There were no detonator placer levers at Helston - it had only, as already noted by 'Railwest',  red (signal), black (point), and blue (facing point lock) levers.

 

The photo below shows a Reading design 5 bar vertical tappet interlocking lever frame  of the type installed at Helston in 1958.  The lever with brown and white horizontal stripes is a King Lever which allows the lever frame to be switched out of use with signals cleared for opposing directions on the single line it controls.  above the lever frame is teh block ashelf (suspended from the roof in the standard GWR manner and above it is the diagram.  The block shelf has various electric release plungers on the front (the things with brass knobs) and above them signal repeaters  (red & white for stop signals, wholly white for slots on something worked by another signal box or ground frame.  there are block bells and signal lamp repeaters mounted on top of  the shelf.

 

Epic. This is what I am lusting after to “drive” my model. I assume the blue levers are FPLs working in reverse direction and the plain whites are spaces in the frame. I have found from guys in another thread a table of colours and uses that is making it all more clear.

But in what era did the shelf with all the indicators appear. The photos of Helston box show no such shelf, I guess the operator worked everything out from the lever positions?

thanks

Andy

[Andy Keane]

On 13/04/2021 at 21:50, James Parker said:

I am struggling to interpret just one element of the signal box diagram produced by the signalling record society for Helston (GWR).  The diagram is here https://www.s-r-s.org.uk/html/gwf/S1195.htm (I wont copy it in case of breach of copyright).

The turnout which connects the engine loop and the siding (on the left hand side of the diagram) doesn't show a  'normal' position, isn't labelled 'sprung' and doesn't have a corresponding lever in the box.  I cant find any evidence in photos of a ground frame nor any reference to one.  So the question is, how was this turnout (and shunting operations in general) worked, particularly in the 1956 layout.  Its clear how you get (or rather a train gets) to the engine loop but not how the train gets to the siding, goods shed and places beyond.  Do I have to infer a ground frame or is there some mechanism, depicted by the symbol which appears on this diagram only for one turnout, which indicates some other means of operation?

'Signal Box Diagrams of the Great Western and Southern Railways (Pryor) has exactly the same symbology but equally no explanation.  Doubtless this is therefore obvious to those with a good knowledge of prototype working practice, but sadly not to me.

In reality on my (very, very slowly emerging) model, the turnout does of course have a point servo, so I can do what I want, but I'm keen to understand how the prototype would have been worked.

James, do you plan to post any photos of “your” Helston. I too am slowly working on such a layout.

[RailWest]

>>> I assume the blue levers are FPLs working in reverse direction....

It was the usual GWR practice for FPL plungers to stand normally 'out', so the lever had to be pulled to lock the point.

 

>>>and the plain whites are spaces in the frame.....

White levers were spares. Spaces were exactly that - a slot with no lever in it :-)

 

>>>But in what era did the shelf with all the indicators appear. The photos of Helston box show no such shelf, I guess the operator worked everything out from the lever positions?

 

You only had a shelf in later years if there was enough instruments to need one. Helston would have no 'block instruments' as such, just the Electric Train Staff machine that would stand in one corner. The bell for it would be on a small shelf on the wall above it. Any arm or lamp repeaters (of which here would not be many) would be put on the window sill and/or fixed to the wall. Telephones would be fixed to the back wall somewhere.

[Nearholmer]

2 hours ago, RailWest said:

It was the usual GWR practice for FPL plungers to stand normally 'out', so the lever had to be pulled to lock the point

That seems entirely illogical to me - I would have expected the normal position to be the safe, locked, one.

 

Was there some logic for doing it as the GWR did it?

[Andy Keane]

A minor question. When do we think the newer striped shunt ahead signal would have been installed at Helston to replace the early “S” pattern type?

[beast66606]

17 minutes ago, Nearholmer said:

That seems entirely illogical to me - I would have expected the normal position to be the safe, locked, one.

 

Was there some logic for doing it as the GWR did it?

 

Most (all ?) companies did it this way, the GWR weren't unique.

[Nearholmer]

But, why?

 

Was it, perhaps, to require fewer pulls, and incur less risk of mistakenly challenging the locking, during shunting operations?

[beast66606]

10 hours ago, RailWest said:

White/Brown = white levers were spares. It was a convention in some places to paint the top half white, but leave the bottom half the original colour to indicate its original function, especially if the locking had not been removed so the lever still needed to be used occasionally. Given that it is a short-handled lever, indicating (usually) that it worked something electrically, it is /possible/ that it had once been a GF release or similar and hence Blue/Brown
 

 

17 used to release McGhies ground frame on the down between Appleby and Culgaith

[beast66606]

3 minutes ago, Nearholmer said:

But, why?

 

Was it, perhaps, to require fewer pulls, and incur less risk of mistakenly challenging the locking, during shunting operations?

 

Because when you look along the frame it's easy to see which points are locked.

[Nearholmer]

I think it must just be me, but I think the thing I’d want to know is which aren’t locked - to me it would seem normal for them to be locked.

 

I guess that part of the issue is around points that are locked both normal and reverse.

 

Anyway, there is a danger that my idle curiosity will divert the thread.

[Michael Hodgson]

5 minutes ago, Nearholmer said:

I think it must just be me, but I think the thing I’d want to know is which aren’t locked - to me it would seem normal for them to be locked.

 

You only need to lock facing points when you're about to run a train over them.  So if there's nowt about, no need to lock any points.  And if everything is normal in the frame, you can see at a glance that you are ready to set up the route for whatever movement might be next.

[beast66606]

14 minutes ago, Nearholmer said:

I think it must just be me, but I think the thing I’d want to know is which aren’t locked - to me it would seem normal for them to be locked.

 

 

That's exactly what looking along the frame tells you - if the lever isn't over the points aren't locked, it doesn't take too long for this to become second nature, a quick glance tells you what you've not locked.

[Nearholmer]

Just the same as, in my fantasy world, a quick glance would identify a lever reversed, showing points unlocked, rather than everything reassuringly normal and locked.

 

I’d wager that somewhere in the world there is a signalling convention that makes locked normal. Any German signalmen present?

[Andy Keane]

Luckily as OO scale modellers I guess few ever install working facing point locks? I plan to go blue over black on the two facing point levers on “my” Helston. Although the frame actually had separate locks it seems blue over black would be correct for a system where a single lever operates and locks the point.

Andy

[Michael Hodgson]

31 minutes ago, Andy Keane said:

Luckily as OO scale modellers I guess few ever install working facing point locks? I plan to go blue over black on the two facing point levers on “my” Helston. Although the frame actually had separate locks it seems blue over black would be correct for a system where a single lever operates and locks the point.

Andy

Yes, that would be correct.  However if a point doesn't have a facing point lock, the lever would be black.  For example a trailing point giving access to a siding wouldn't need an FPL, so its lever would be black.  Of course if that point were motor-worked, the point motor comes with a built-in FPL, so the lever would be blue over black, and the lever handle would be cut down.

[beast66606]

47 minutes ago, Nearholmer said:

Just the same as, in my fantasy world, a quick glance would identify a lever reversed, showing points unlocked, rather than everything reassuringly normal and locked.

 

Everything wouldn't be normal though, points and signals would be reversed.

To a signalman the act of pulling a lever means a positive action has been done on the ground viz a point reversed, a signal cleared, - or a point locked, why make FPLs behave differently ?

 

Anyway we digress ...

[Andy Keane]

6 hours ago, Michael Hodgson said:

Yes, that would be correct.  However if a point doesn't have a facing point lock, the lever would be black.  For example a trailing point giving access to a siding wouldn't need an FPL, so its lever would be black.  Of course if that point were motor-worked, the point motor comes with a built-in FPL, so the lever would be blue over black, and the lever handle would be cut down.

Indeed, the original track plan when Helston was built deliberately avoided all facing passenger carrying points and even when relaid never had more than two. These are the two I shall use multi coloured levers on. See also my thread on my build (page 3): 

 

Edited July 7, 2021 by Andy Keane

[5BarVT]

11 hours ago, Nearholmer said:

That seems entirely illogical to me - I would have expected the normal position to be the safe, locked, one.

 

Was there some logic for doing it as the GWR did it?

Standing ‘normally out’ means the FPL will be normal order to move the points. Given that FPLs were often adjacent to the point they locked it made it a lot easier to avoid a ‘pull between’ when designing the frame.  Old fashioned health and safety from before it was called that!

Paul.

[The Stationmaster]

14 hours ago, Nearholmer said:

That seems entirely illogical to me - I would have expected the normal position to be the safe, locked, one.

 

Was there some logic for doing it as the GWR did it?

Very logical in working and locking terms.  As you set a route (through facing points) the last things you do before clearing the signals is to lock the route. (although in many long  leads you would probably be bolting some FPLs before you have set all the points  to save walking back to them because of the way the frame was laid out.   The  other big advantage was that it was always obvious from a glance at the frame if a point was bolted because a reversed lever is much more noticeable than one standing normal among various others standing normal.  This is particularly useful if - for whatever reason. -you can't get a signal lever to reverse or a signal to clear - a quick glance along the frame and the blue levers standing reverse stand out in your line of sight, very handy if you had to flag a signal.

 

The debatable area is whether or not FPLs standing bolted reverse saves lever movements.  However when the WR applied work study principles to the planning and layout of lever frames (having first spent a lot of time conducting work studies in numerous signal boxes) with the main aim of reducing workload through cutting the number of lever movements and reducing the amount of walking up and down a long frame the principle of bolting by lever reversed was not changed although there was specific aim of reducing costs by reducing the number of lever movements.   Oddly in that respect the Western never adopted the standard SR method of arranging the normal lie of points at a double track junction because, assuming the facing point is always bolted. the Southern arrangement saved one lever movement in some situayions.

 

As an aside one trick - among many - employed by Signalmen when the marks were being taken to grade a 'box was to still bolt facing points when they were used for trailing movements although it was one that was readily seen through by experienced assessors - unlike 'the telephone calls trick' which was very difficult to disprove. 

[Joseph_Pestell]

On 14/04/2021 at 22:15, James Parker said:

 

 

Its a great story, I have no idea if its true, and nor have I any idea how to model it (in 2mm finescale) other than the obvious one of building a coach with a fully driven bogie, which seems a bit excessive.  It would make a nice trick for a model though!

 

Assuming that you have modelled the gradient:

 

A pin operated by a servo or solenoid comes up in the "4ft" to act as a brake on one of the axles of the train.

[Andy Keane]

58 minutes ago, Joseph_Pestell said:

 

Assuming that you have modelled the gradient:

 

A pin operated by a servo or solenoid comes up in the "4ft" to act as a brake on one of the axles of the train.

I am pretty sure Tony doing the Cartoon of Helston(ish) does have the gradient modelled. Maybe somewhere in his thread you may find this in action: