Signalling help + Interlocking

[bécasse]

2 hours ago, Stephen Freeman said:

Forgive me but I thought that point indicator ground signals were done away with fairly early in the 20th century as they were frowned upon by the Railway Inspectorate due to the possibility of them showing a safe to proceed indication when they shouldn't (usually due to wear in linkages). Not sure of exact date but possibly some lingered on in a few backwaters.

Yes but the Inspectorate obviously failed to get the message through to the GWR! In practice the point indicator would have been installed as part of the original installation and never changed (and nor would the Inspectorate have asked for it to be changed), Highworth, not far from Swindon, was an obvious example.

[Henry.]

Would the arrival signal be on scene?

[The Stationmaster]

1 hour ago, Henry. said:

It would also be good if anyone had any advice about interlocking for this plan

Hmm,  Well really it boils down to do you need it on a simple model railway track layout (probably 'no').  or do you want to havea go at it (sounds like it might be 'yes')

 

For the signalled layout we have now arrived at the locking will be very straightforward with nothing more complex than ordinary locks and releases, nothing conditional (the difficult bit) or even very  much in the way of multiple locks on a single.

 

First number everything -

1. Down Home Signal

2. Disc main line to loop (aka 'Disc For 3 points')

3. Crossover main line to loop

4. FPL for .  (FPL = Facng Point Lock)

5, Engine Release Points and Indicator

6. Disc Loop to Main Line

7. Platform Starting signal

 

1.  Released by 4,       Locks 3, 5, 7.   Releases Nil.

2.  Released by 3, 4.  Locks 6             Releases Nil

3.  Released by Nil.    Locks 1, 5, 7.   Releases 2,6 

4.  Released by Nil,    Locks 3 BW.    Releases 1,2.        n.b. 'BW' = Locks both ways

5.  Released by Nil.    Locks 1, 3, 7    Releases Nil

6.  Released by 3.      Locks 2.            Releases Nil

7.  Released by Nil.   Locks 1, 3, 5.    Releases Nil 

Edited August 9 by The Stationmaster

[The Stationmaster]

10 minutes ago, Henry. said:

Would the arrival signal be on scene?

 

Yes, it needs to close to the point toe.

[Henry.]

It might be difficult to see with the bridge though, would there of been a high signal?

[Henry.]

Also when running around would signal 1 be pulled?

[Henry.]

Also would the token need to be out for running around as their is no signal further down the line?

[The Stationmaster]

44 minutes ago, bécasse said:

Yes but the Inspectorate obviously failed to get the message through to the GWR! In practice the point indicator would have been installed as part of the original installation and never changed (and nor would the Inspectorate have asked for it to be changed), Highworth, not far from Swindon, was an obvious example.

The important was the Requirements and non-independent point indicators were not outlawed by either the 1902 or 1922 revision.  They remained in the WR Regional Appendix until at least 1967 which suggests that there were still some around in the mid 1960s.  One I know of, ona. release crossover, was not installed until 1911

 

There is incidentally no mention of them at all in the relevant GWR minute book running up to 1920 which suggests that the company had received no suggestions about their removal up to that date.

[The Stationmaster]

15 minutes ago, Henry. said:

Also when running around would signal 1 be pulled?

Possibly although technically it shouldn't be (but out of sight and mind of officialdom things were done to suit those on the ground).

 

14 minutes ago, Henry. said:

Also would the token need to be out for running around as their is no signal further down the line?

As mentioned by Harleqiuin the line would have been worked on a One Engine In Steam  (OES) basis which would have meant a Train Staff, nota token.  it might well have been surrendered on arrival but it might have been left on the engine.  Whichever of those makes little difference because shunting onto the single line was no problem with the Train Staff at this end of the branch.

[RailWest]

6 minutes ago, The Stationmaster said:

As mentioned by Harleqiuin the line would have been worked on a One Engine In Steam  (OES) basis which would have meant a Train Staff, nota token.  it might well have been surrendered on arrival but it might have been left on the engine.  Whichever of those makes little difference because shunting onto the single line was no problem with the Train Staff at this end of the branch.

But, as has been mentioned already IIRC, if it was indeed OES working on the section to the terminus then surely any signal and signal-box would have long been recovered and replaced by a GF or two (eg Abbotsbury, Clevedon etc) ??

 

The complexity - or lack of it - in the layout surely was not a pre-requisite for ETS or EKT working (or maybe TS&T) and the GWR had many small termini with just one platform and a run-round loop and a few sidings worked by those methods. At least it would give the OP a bit more flexibility should he so wish it.

[Jeremy Cumberland]

A few thoughts.

 

First of all, @Henry. needs to decide whether a second train might arrive while another train with locomotive is already in the station. It might not seem very prototypical given the track plan, but it would make for a more interesting layout to operate, I think, and it is certainly what I would choose. This straightaway rules out one engine in steam (OES), and although it might not have a great effect on the appearance or location of signals, I imagine it will change how they are worked. [Question for @The Stationmaster or others with knowledge of such things: If the line is worked OES but signals are still provided, would both home and starter be cleared before the train departs.]

 

Aberayron was given as an example of a GWR branch line terminus in Wales earlier in this thread, and the signal box diagram is at odds with a couple of statements made in this thread.

 

1 hour ago, The Stationmaster said:

But you need the ground disc by the Home signal once you start shunting wagons off your freight train after the engine has run round the train.

Aberayron doesn't have a shunt signal for entering the goods yard (but there is one for exiting it). I take it the movement was handsignalled from the signal box.

 

1 hour ago, Michael Hodgson said:

Selected signals were usually provided where a layout had been expanded, all the spare levers had been used, and so you appeared to need a longer lever frame, and probably also an extension to the building.  The locking of such signals is more complex and they need more maintenance, so you probably wouldn't usually design it in at the outset, so I don't think that's likely here.

Aberayron had selected signals for platform departure/yard exit, combining The Stationmaster's levers 6 and 7. I've never worked for S&T but I never thought signal selection mechanisms were particularly complicated, although I agree they are something else to maintain, particularly as lever 1 at Abarayron would not otherwise need point detection. Interlocking within the frame barely changes: the signal lever locks the point lever each way rather than in one position.

 

A couple of comments for anyone puzzled by the following:

• The Stationmaster numbered his levers the other way round from Aberayron because the platform, and presumably the signal box, is on the opposite side of the line.
• The Stationmaster has 7 levers and Aberayron appears to need 2 levers fewer, yet it has 6 levers. The extra one is for an advance starter.

2 hours ago, Henry. said:

How would the selection work, and also would you use the shunt or the stop signal for running around?

The signal wire pulls on a pulley. The two signals are linked by a wire that passes round the pulley, with a point detector on either side. Each detector only allows the wire to move if the points are set a certain way. When the signal lever is pulled, this moves the pulley. The wire on one side of the pulley is locked by the detector on that side but the other side should be free, and so this gets pulled and the signal attached on this side clears.

 

The two signals are for different routes. Use whicher one applies for the route the loco is to pass over.

[Henry.]

I would like to have more then 1 loco for operational interest, one could go infront of the goods shed or in the cattle dock siding. Do you think the visibility will of been poor if the signal for the platform / yard is close to the bridge

[Henry.]

Also if their is more than one train, will you need to clear the run-around onto the main line or shunting from the siding to the goods shed with the next signal box?

[Henry.]

I've bought a ground frame hut which is slightly raised which I might mount to the platform

[Stephen Freeman]

IMHO only if you go out of section, depends where your starter signal is, in some cases you could have an outer starter (unlikely here because of the space), so best have a shunt ahead arm on the starter post as well.

[RailWest]

6 minutes ago, Stephen Freeman said:

IMHO only if you go out of section, depends where your starter signal is, in some cases you could have an outer starter (unlikely here because of the space), so best have a shunt ahead arm on the starter post as well.

I'm not sure what you mean by "going OUT of section"?

 

Although the GWR seemed far more keen on SA arms than (say) the L&SWR at BLTs, IMHO they tended to be on Advanced Starting signals. I'm not aware of any on a Starting signal where that was also the section signal - take Princetown as an example. Given the likely location of the signal-box, a hand-signal and/verbal instruction from the signalman would probably have been deemed adequate.

[The Stationmaster]

4 hours ago, Stephen Freeman said:

IMHO only if you go out of section, depends where your starter signal is, in some cases you could have an outer starter (unlikely here because of the space), so best have a shunt ahead arm on the starter post as well.

That I'm sorry to say is a nonsense.  A Shunt Ahead subsidiary could only be mounted below the  most advanced signal reading towards/into a section.   You can't put one below any stop signal applying in the same direction reading towards the most advanced stop signal - basically because there's no need to do so.   Similarly there isn't really much need for an Advanced Starting Signal at many single line stations so they didn't have them

 

In fact you don't need any sort of fixed signal, such as a Shunt Ahead subsidiary below the signal reading into the a single line section, unless the number and frequency of movements and the distance from the signal box created a reasonable need for one.  As already mentioned the Driver is simply instructed to pass the signal at danger once the Signalman has obtained authority from the next signal box for the movement to take place.   But even the last bit isn't necessary if it is a One Engine In Steam (OES) section because the Train Staff is at that end of teh section in any case.

 

Incidentally quite a number of GWR OES sections retained a 'signal box', often reduced to the status of a ground frame but still with signals, into the 1960s or to closure.  For example Wallingford retained its until 1964, long after the line had been reduced to freight only working and it was far from alone in that situation.

[Stephen Freeman]

I think you misunderstood what I was saying, only that if there was no advanced starter, you could have a shunt ahead, reading the situation, there would be more than one engine in steam and it would be a regular and frequent move.

[The Stationmaster]

55 minutes ago, Stephen Freeman said:

I think you misunderstood what I was saying, only that if there was no advanced starter, you could have a shunt ahead, reading the situation, there would be more than one engine in steam and it would be a regular and frequent move.

Sorry but to me  'as well' doesn't mean the same as 'instead of'

[Stephen Freeman]

the as well referred to the stop arm

[5BarVT]

On 08/08/2024 at 22:05, Jeremy Cumberland said:

I wouldn't get bogged down in terminology. @5BarVT called Aberaeron lever 1 "Up Home", and since he knows far more about signalling than I do, I for one am not going to argue.

Thanks for the mention.  I agree about not getting bogged down in terminology - especially as Hornby et al call stop signal models Home Signals so that is the natural term to use as a beginner.

As for me calling Aberaeron no. 1 a home signal: Oooops!  I wouldn’t now, and I think it might have been an aberration then.

Paul.

 

Edited August 11 by 5BarVT
Spelling - me not the iPad for once.