Colour light shunt signals

[Ray H]

I believe that modern day colour light shunt signals show two horizontal red lights when at danger and two diagonal white lights when clear.

 

Am I correct in thinking that this is a recent development and that some years ago the danger display was one red & one white horizontally. That is the bottom right hand corner "light" (when looking at the illuminated face side) was always white and permanently on, the bottom left only ever red when illuminated and the upper left only ever white when illuminated.

 

Does anyone know when the change occurred and whether the old arrangement still exists in places?

 

I'm about to build a 7mm version for a colleague for his early BR blue based layout and want to get the illuminated colours right.

 

Thanks.

[Rivercider]

You are correct about the arrangement of lights, though I don't know when the change took place,

 

This is Newport in 1980

31205 at Newport 15/7/80

 

cheers

[RailWest]

Essentially you are correct in your assumption about the earlier style.

 

Do not forget however - in case it is applicable to your model - that there was also a version with yellow instead of red (although I'm not sure if any modern 'double yellow' examples exist), and that subsidiary signals (provided for 'calling on' purposes ) were only two whites at an angle and ONLY illuminated when 'off'.

[Suzie]

The new type that show two reds are very new LED type so you won't want that type for early blue. The only exception are the 'fixed red' limit of shunt type which display two reds rather than one red and one white.

[Nick G]

I believe they changed sometime in the 90's.

 

 

[TheSignalEngineer]

I don't know the actual date of introduction of the two reds version but it was definitely in the 1996 standard relating to lineside signal aspects.

 

https://www.rssb.co.uk/rgs/standards/GKRT0031%20Iss%201.pdf - see Part B section 5.5 on page 17

[Edwin_m]

subsidiary signals (provided for 'calling on' purposes ) were only two whites at an angle and ONLY illuminated when 'off'.

Just to clarify, this refers to a subsidiary aspect below a main signal.  Except in case of lamp failure a shunting signal would always display two lights. 

[big jim]

 

Does anyone know when the change occurred and whether the old arrangement still exists in places?

 

 

 

 

one place they still exist (odd as it is) is on the WCML just north of Rugeley trent valley station for the shunt across the ladder from the cannock line

 

i'm sure more will come up but i'm struggling to think of any more off hand

[St. Simon]

Do not forget however - in case it is applicable to your model - that there was also a version with yellow instead of red (although I'm not sure if any modern 'double yellow' examples exist

  

 

There is certainly a 'yellow-yellow' shunt at Swindon Yard, although they are very rare nowadays, as there is a preference to have 'Red-Red' signals instead.

 

one place they still exist (odd as it is) is on the WCML just north of Rugeley trent valley station for the shunt across the ladder from the cannock line

 

i'm sure more will come up but i'm struggling to think of any more off hand

Although I can't think of many nowadays, there has been a national campaign to replace all 'Red-White' with 'Red-Red' versions, even those with aren't used anymore, so doubt that there many more than the odd one or two!

 

Simon

[jim.snowdon]

I don't know the actual date of introduction of the two reds version but it was definitely in the 1996 standard relating to lineside signal aspects.

 

https://www.rssb.co.uk/rgs/standards/GKRT0031%20Iss%201.pdf - see Part B section 5.5 on page 17

The critical factor is the development of high output white LEDs, which didn't happen until at least the late 1990s, which essentially means that any three lamp shunt signal in the pre-Railtrack era would have to be red/white - white/white.

 

Jim

[Ray H]

Many thanks for all the info. I've realised that I got the orientation wrong in my initial post. For some reason I thought it was the bottom left white that was common to "on" and "Off" but the first picture posted above confirms it should have been the other way round.

[The Stationmaster]

I believe that modern day colour light shunt signals show two horizontal red lights when at danger and two diagonal white lights when clear.

 

Am I correct in thinking that this is a recent development and that some years ago the danger display was one red & one white horizontally. That is the bottom right hand corner "light" (when looking at the illuminated face side) was always white and permanently on, the bottom left only ever red when illuminated and the upper left only ever white when illuminated.

 

Does anyone know when the change occurred and whether the old arrangement still exists in places?

 

I'm about to build a 7mm version for a colleague for his early BR blue based layout and want to get the illuminated colours right.

 

Thanks.

 

Campaign change from, roughly, the mid/late 1990s onwards.  I understand that the idea was twofold - partly to bring them into line with Limit of Shunt signals (a gpl showing two reds) which had been introduced to improve on the various illuminated signs previously used in order to reinforce the message but far more importantly to ensure that in the event of a lamp failure there would still be another one showing red when the signal was at danger.

 

The main changeover campaign took a long time - still going on in the early 2000s and even then some might have escaped the net, as Jim indicated above

[big jim]

Another that escaped Is the rear bulb illuminated "SHUNT LIMIT" sign on the Chester line out of crewe!

[big jim]

here is one of the rugeley signals

 

 

i'll be honest and say im struggling to see what its there for, i can only assume its so trains/locos/plant etc can leave the sidings and head north towards the south facing main aspect to come back across the ladder, the other odd thing is there is no position light into the sidings from the platfrom end (where i took the picture from) not sure if they are ground frame worked (there looks to be one on the photo) and authority to enter/leave is via a shunter/groundstaff after obtaining release from the box

Edited April 21, 2017 by big jim

[Edwin_m]

i'll be honest and say im struggling to see what its there for, i can only assume its so trains/locos/plant etc can leave the sidings and head north towards the south facing main aspect to come back across the ladder, the other odd thing is there is no position light into the sidings from the platfrom end (where i took the picture from) not sure if they are ground frame worked (there looks to be one on the photo) and authority to enter/leave is via a shunter/groundstaff after obtaining release from the box

I think the point is worked by a crank and rodding that disappears behind the building, not by a point machine.  That set of points is also likely to be worked with a trap point, which I think is peeking out from behind the same building with more rodding linking it to the ground frame. 

[big jim]

the building looks to be the base of an old signal box, its a trick of the photo but the points are quite a way back from it but agreed the rodding looks to be heading behind the building to the groundframe, i never thought to have a look, or indeed that it was odd there was no signal for the sidings until i uploaded the picture after id left rugeley station!

 

the other oddity is, as far as i know there is no limit of shunt futher north (ie after the southbound facing main aspect) so if a driver took that signal there (technically) would be nothing to stop them continuing north as far as they wanted wrong road, the only other thing i can think of is the ground signal in wuestion is being used as a limit of shunt, meaning anything leaving the sidings would have to go all the way to lichfield north jn to be able to head back north

 

im going to have to look into this one as i sign the route and sods law i'd have a tamper conducting move out of there one day!

Edited April 21, 2017 by big jim

[TheSignalEngineer]

the building looks to be the base of an old signal box, its a trick of the photo but the points are quite a way back from it but agreed the rodding looks to be heading behind the building to the groundframe, i never thought to have a look, or indeed that it was odd there was no signal for the sidings until i uploaded the picture after id left rugeley station!

 

 

The building is the Relay Room put there c1962.

[The Johnster]

The yellow version of the ground position light shunting/subsidiary signal was always a rarer beast.  It was used where a GPL controlled an exit from a yard or sidings to a main running line, but there was also a headshunt or more sidings in the 'straight on' direction.  A driver could pass it at caution, i.e. when it showed the yellow and white lights horizontally (or the more recent, and rarer, 2 yellows horizontally) only if the road was set to the direction to which the cleared signal did not apply, that is, up the headshunt.  A driver was not authorised to pass it at caution if the road was set for the running line, and would have to come to a stand at it until it was cleared, showing 2 white lights diagonally up to the left.  All moves authorised by subsidiary signals, whether GPLs or 'Calling on' signals on the lower part of main signal posts, must be carried out under caution, with the driver instructed to drive at such a speed as he can stop from in the distance he can visually confirm is clear ahead, and in any case at no more than 15mph.  Acceleration to line speed does not take place until the driver is given a 'clear' yellow, double yellow, or green aspect from a main signal, and not until the entire train is clear of any speed restricted junction or curve it has passed through.

 

By and large, as far as models are concerned, shunting should take place at a suitably low speed, as should departures of freight trains from sidings or yards until the last wagon is clear of the exit and on the running line proper.

 

Hope that is of some use to you and your friend's new layout!

[Mark Saunders]

It has been an ongoing thing since the mid 1990's with replacement heads being fitted later to remaining ones!

 

At a similar time the Limit of Shunt boards were getting replaced with a GPL permanently set with two Reds!

 

The GPL's that remain red and white are those tend not to be on Network Rail infrastructure, such as Yards and Depots!

 

Mark Saunders

[iands]

Hi all,

 

I agree with the comments regarding the transition from Red-White GPLs to Red-Red GPLs. IIRC there was also sort of "half-way house" approach for a while where two horizontal Red lights were displayed at the bottom (when the signal was 'on'), and two white lights at 45 degrees above them (when the signal was 'off') in the same GPL unit, e.g a GPL with four lights. Does anyone else remember these?

 

Regards, Ian.

[Mark Saunders]

Hi all,

I agree with the comments regarding the transition from Red-White GPLs to Red-Red GPLs. IIRC there was also sort of "half-way house" approach for a while where two horizontal Red lights were displayed at the bottom (when the signal was 'on'), and two white lights at 45 degrees above them (when the signal was 'off') in the same GPL unit, e.g a GPL with four lights. Does anyone else remember these?

Regards, Ian.

The display remains constant it is all down to the manufacturer as to how the signal is built! The only place I recall separate white and red is Manchester North resignalling, more in the hidden message way as with illuminating signs on doors.

 

Mark Saunders

[stadman]

Depot protection GPL's still have the old Red/ white or 2 white format (some areas)