Black and Yellow Shunting Signals

[Western 52]

At Abergavenny yesterday I noticed a black and yellow shunting disc, which can be passed at danger in one direction, but not the other. In this case it allows moves from the loop to a siding, but would need to be pulled off for a move to the main line. I can't remember seeing one of these anywhere else recently, are there many left elsewhere?

The picture shows the black and yellow disc signal at Abergavenny on 23 July 2024.

 

[DoubleO]

I think there's still one at Harrogate. They're certainly few and far between though. There used to be one at Barnetby but it was removed during resignalling 7-8 years ago.

 

[John Webb]

There are some around, and the GPL (Ground position light) equivalent as well, but I believe they are not recommended for modern signalling systems; I'm not quite clear what the argument against them is.

 

[Islineclear3_1]

I think there is still one at Canterbury West...(?) Or is it a black stripe on yellow disc...

 

[Wilts Wanderer]

Not on Network Rail, but there is a yellow shunting disc at Highley protecting the north exit from the yard. A shunt move along the headshunt passes it at danger. (From memory it is a yellow bar on a white background, but the meaning is the same.) I believe it is soon to be replaced as the SVR intend to more comprehensively signal Highley including fully controlled shunting signals for entry and exit - currently Up yard arrivals are undertaken by hand signal from the box.

 

[John Webb]

I think there is still one at Canterbury West...(?) Or is it a black stripe on yellow disc...

Most likely Yellow stripe on Black disc. SR (both before and after 1948) in electrified areas tended to floodlight disc signals rather than the more usual arrangement of a lamp behind shining through coloured holes in the disc. They found the yellow bar on a white disc wasn't easy to see, hence the change to a black background. This was adopted elsewhere on BR over the years.

 

[Wilts Wanderer]

Questions about loco driving inside a freight yard

I was watching a Class 66 being driven around inside a freight yard and two things surprised me: - The sun was going down and it was dusk. The driver started the Class 66 and drove away from me with no rear red lights illuminated, then reversed and drove past me with front white lights...

www.railforums.co.uk

Previous discussion on this topic from post #13

 

[Islineclear3_1]

Most likely Yellow stripe on Black disc. SR (both before and after 1948) in electrified areas tended to floodlight disc signals rather than the more usual arrangement of a lamp behind shining through coloured holes in the disc. They found the yellow bar on a white disc wasn't easy to see, hence the change to a black background. This was adopted elsewhere on BR over the years.

Thanks, that is what I "think" I remember...memories fade over the years....

 

[Arewethereyet?]

One example still at Worcester Shrub Hill.

 

[Western 52]

One example still at Worcester Shrub Hill.View attachment 162309

That has the old type lamp too. What colour lights do these discs have?

 

[Boilinthebag]

Just to add to this, these aren't passed at danger. The signal does not apply/is disregarded for movements not towards the main line. In effect the signal does not exist until the train requests a route/is routed towards the main line. The old BR signalling video on YouTube has a good example of one in action.

 

[edwin_m]

There are some around, and the GPL (Ground position light) equivalent as well, but I believe they are not recommended for modern signalling systems; I'm not quite clear what the argument against them is.

Certainly by the late 1980s when I was involved in IECC schemes, the preference was to have back to back shunt signals which remained permanently "off" for movements not going to the main line, and were restored to danger while the points were switched for a move to or from the main line.

 

[zwk500]

There are some around, and the GPL (Ground position light) equivalent as well, but I believe they are not recommended for modern signalling systems; I'm not quite clear what the argument against them is.

My understanding is that yellow and black shunting signals were introduced to save the signaller frequent operation of a shunt signal in busy areas, which was both a benefit for the signaller and saved on wear for the signal. It possibly also reduced the need for individual discs for the routes being protected.
I would guess that the maintenance issue isn't a factor with colour-light shunt signals, and that as computerised controls (including slots given to a depot/yard) have come in, and route indications are provided, there's no real benefit to having a slightly different form of shunt signal.

Interestingly, Signalmaps indicates at Bristol TM https://signalmaps.co.uk/#gwml9:1633 that there's a yellow shunt signal controlling the exit at the London ends of Bristol East depot (bottom) and Barton Hill Depot (top), but the arrangement @edwin_m describes is present at the country end of Barton Hill Depot. The shunt signal is normally 'off' reading to the headshunt (which has a Stop board protecting the exit) but then changes to on if a train is signalled to or from the main line. Certainly for Barton Hill, the overwhelming majority of shunt moves are made at the end with the Red GPL.

 

[John Webb]

That has the old type lamp too. What colour lights do these discs have?

Yellow and Green - the latter when the move onto the main line is cleared. That particular signal in #9 is, I believe, electrically lit; I recall reading all the mechanical signals in the area are.

 

[Tractor37]

I think there's still one at Harrogate. They're certainly few and far between though. There used to be one at Barnetby but it was removed during resignalling 7-8 years ago.

Your thinking is right - there is one at Harrogate, at the north end of the station.

 

[Ashley Hill]

There are two yellow discs (yellow stripe/white background) at Bishops Bridge on the SDR.
Locally there are several yellow GPLs. Keyham,Exmouth Junction and Bridgewater spring to mind.

 

[Belperpete]

There are some around, and the GPL (Ground position light) equivalent as well, but I believe they are not recommended for modern signalling systems; I'm not quite clear what the argument against them is.

The problem is that there is nothing to prevent the signaller from changing the points beyond the disc while a loco is running up to it at ON and the driver intending to pass it. Perhaps not too bad in situations where the signaller has visibility of moves approaching the signal, but an accident waiting to happen where the signaller is miles away and has no way of knowing about the approaching loco.

I once came across a case of a fixed yellow disc, at Poole IIRC. The crossover to the main had been taken out, but for some reason the yellow disc in the yard had been left.

 

[Railsigns]

I once came across a case of a fixed yellow disc, at Poole IIRC. The crossover to the main had been taken out, but for some reason the yellow disc in the yard had been left.

I've seen the opposite situation where the headshunt had been removed, but the signal was still coloured yellow.



[Photo shows a yellow disc signal at Cobh, Ireland]

 

[DoubleO]

The problem is that there is nothing to prevent the signaller from changing the points beyond the disc while a loco is running up to it at ON and the driver intending to pass it. Perhaps not too bad in situations where the signaller has visibility of moves approaching the signal, but an accident waiting to happen where the signaller is miles away and has no way of knowing about the approaching loco.

I once came across a case of a fixed yellow disc, at Poole IIRC. The crossover to the main had been taken out, but for some reason the yellow disc in the yard had been left.

Surely there'll be something in the regs to prevent that happening, either direct line of sight from the box or some alternative measure such as a track circuit etc?

 

[Belperpete]

I've seen the opposite situation where the headshunt had been removed, but the signal was still coloured yellow.

View attachment 162364

[Photo shows a yellow disc signal at Cobh, Ireland]

A square disc!

== Doublepost prevention - post automatically merged: 26 Jul 2024 ==

Surely there'll be something in the regs to prevent that happening, either direct line of sight from the box or some alternative measure such as a track circuit etc?

I can think of some yellow GPLs where the power box would have had no line of sight, such as Old Oak. Don't see how a track circuit would help - it tells you something is there, but not whether it is moving, let alone in which direction.

 

[edwin_m]

Don't see how a track circuit would help - it tells you something is there, but not whether it is moving, let alone in which direction.

If there is a yard where shunting takes place, the signaller will need to come to some arrangement with the person in charge whether it's for a train entering the yard (so they can confirm there is a clear track to put it on) and when leaving (because it won't be signalled until it is ready). One or other has to be agreed before the signaller will consider reversing the points, and neither is possible if there are trains moving around that might be passing over those points.

 

[ex-probationer]

I think there is still one at Canterbury West...(?) Or is it a black stripe on yellow disc...

I've just checked, as I took photo's of Canterbury West on 17/07/2008, whilst on duty. Seems there were two at that time, not sure if they still exist.







Also found in my collection, a Yellow GPL photographed at Gillingham, Dorset on 5/11/2009. This was before the West of England resignalling, guess it's gone now!

 

[Islineclear3_1]

Lovely pics, thanks for posting. My memory wasn't quite deceiving me then - just I'd forgot there were 2 of them....

 

[DoubleO]

A square disc!

== Doublepost prevention - post automatically merged: 26 Jul 2024 ==


I can think of some yellow GPLs where the power box would have had no line of sight, such as Old Oak. Don't see how a track circuit would help - it tells you something is there, but not whether it is moving, let alone in which direction.

A TC would help if the signaller wasn't allowed to change the points if the circuit was occupied.

 

[jupiter]

I can think of some yellow GPLs where the power box would have had no line of sight, such as Old Oak. Don't see how a track circuit would help - it tells you something is there, but not whether it is moving, let alone in which direction.

Wouldn’t the signalling be interlocked so the points can’t be moved if the track circuit is occupied?

 

[edwin_m]

Wouldn’t the signalling be interlocked so the points can’t be moved if the track circuit is occupied?

It would, but it doesn't help if a train shunting is approaching within the yard, hasn't got to the track circuit but is unable to stop in time. However, the consequence relatively minor: damage to points if trailed through, low-speed derailment of a train with no passengers, or a train continuing a short distance towards or onto the main line where there can't be another train passing.

 

[Falcon1200]

the preference was to have back to back shunt signals which remained permanently "off" for movements not going to the main line, and were restored to danger while the points were switched for a move to or from the main line.

Such an arrangement also existed in non/pre IECC areas. For example, in the Glasgow area for the Depot headshunts at Shields and Polmadie (Shawfield end).

 

[John Webb]

I've just checked, as I took photo's of Canterbury West on 17/07/2008, whilst on duty. Seems there were two at that time, not sure if they still exist.

View attachment 162441


View attachment 162444


Also found in my collection, a Yellow GPL photographed at Gillingham, Dorset on 5/11/2009. This was before the West of England resignalling, guess it's gone now!


View attachment 162449

Interesting that these two disc signals have an electric lamp and the coloured 'spectacle' glasses rather than being floodlight as I've seen the majority of SR discs (yellow or the more common red).

 

[Islineclear3_1]

Interesting that these two disc signals have an electric lamp and the coloured 'spectacle' glasses rather than being floodlight as I've seen the majority of SR discs (yellow or the more common red).

I can't remember if the 2003 resignalling had anything to do with it - abolition of remaining semaphores/colour light installation. Maybe the shunt discs were "upgraded" to electric lights at the same time?

 

[Railsigns]

The Southern Railway/Southern Region only used floodlit disc shunting signals in colour light signalling areas. This was in response to a recommendation of a sub-committee of the Railway Clearing House in 1934 that shunting signals in colour light areas should be of the 'position' type (as opposed to displaying miniature 'colour' aspects). The exact type of signal was not specified. Alternative solutions adopted by the other companies included the use of banner type shunting signals or position light signals. The Southern Region began installing position light signals in the early 1960s.