Gwr ground disc colours

[Junctionmad]

Can someone confirm what the colours on the reverse of the ground discs were . I have seen white , black , white with the  metal bar black, but I’m loathe to rely on preserved railways colours 

 

I see also in preserved railways part of the balance bar , weight and blinder were white , I presume this is a more modern H&S requirement 

 

thanks 

 

Dave 

Edited August 30, 2019 by Junctionmad

[Miss Prism]

http://www.gwr.org.uk/no-groundsigs.html

 

[Junctionmad]

Thank you , I’ve seen that site 

 

but it shows exactly my problem. Many variants 

[bécasse]

Not really many variants. The early "shaped" disc appears to have been produced enamelled white all round (apart, of course, from the red bar) which is quite logical. One presumes that it proved difficult to keep the back of the disc clean and so the lamp blinder was painted white instead and this became the new standard arrangement, carried forward on to round discs when they appeared (with back faces enamelled black). The white backs of the original discs would have been allowed to become grimy over time, other than in odd locations with keen S&T gangs who still cleaned them. All those gwr.org photos are consistent with that analysis.

[Junctionmad]

Thanks , so for round disks , black backs with white blinders 

 

were the balance weights white in gwr days , doesn’t seem so in the pics 

[The Stationmaster]

Right time to sort things -

 

1.  The 1911 'half disc' type was added to the front of the existing miniature semaphore arm independent ground signal which had a cast iron 'arm' (originally painted signal red in the front).  The half disc had the red line on the front but overall, including the back, was in stove enamelled white.

2. The subsequent various designs and sizes of 'full disc' were no different - the back of the disc itself was still white and from every example I have ever seen that remained the case for as long as these 'arms' were manufactured.  The only variation - and I have never seen the back of one - was the yellow on black 'arm' which I would presume was probably black on the back simply because it was the main colour

3. But the big difference with later designs, except the taller one from between the wars - c.1920s,  was that none of the enamelled arm was visible at the back because it was mounted on a similar size casting.  This is visible in pictures on the website linked by Miss P.  The difference with the tall style was that the casting did not cover the whole of the back of the enamelled 'arm' and it was white - as long as it was  kept, or remained, clean.

4. Standard paint style for all the older types of ground discs was that all metalwork except the 'arm' was black after the change from a 'red lead' type of colour (I don't know when that changed I'm afraid  but probably 1920s at the latest - someone might have a researched date for us?)

5. The only divergence from black was when the Post WWII tubular steel post style was introduced where even on the short ground signals it was painted aluminium colour (and probably white in earlier schemes before aluminium was adopted) and aluminium was used on part of the balance weight lever as well - everything else was black.  However painting gang styles did vary a bit, for examples I have seen instances of the back of the cast disc painted in aluminium instead of black but it was unusual in my experience..

 6. In later years the back blinder was painted either white or aluminium but I don't know when that colouring was introduced and it might even have been in the 1907 S&T Painting Instructions (which I don't have immediately to hand, sorry) 

7. Balance weights always appear to have been black after the 'red lead' colour was replaced by black.

[Harlequin]

10 hours ago, The Stationmaster said:

Right time to sort things -

 

1.  The 1911 'half disc' type was added to the front of the existing miniature semaphore arm independent ground signal which had a cast iron 'arm' (originally painted signal red in the front).  The half disc had the red line on the front but overall, including the back, was in stove enamelled white.

2. The subsequent various designs and sizes of 'full disc' were no different - the back of the disc itself was still white and from every example I have ever seen that remained the case for as long as these 'arms' were manufactured.  The only variation - and I have never seen the back of one - was the yellow on black 'arm' which I would presume was probably black on the back simply because it was the main colour

3. But the big difference with later designs, except the taller one from between the wars - c.1920s,  was that none of the enamelled arm was visible at the back because it was mounted on a similar size casting.  This is visible in pictures on the website linked by Miss P.  The difference with the tall style was that the casting did not cover the whole of the back of the enamelled 'arm' and it was white - as long as it was  kept, or remained, clean.

4. Standard paint style for all the older types of ground discs was that all metalwork except the 'arm' was black after the change from a 'red lead' type of colour (I don't know when that changed I'm afraid  but probably 1920s at the latest - someone might have a researched date for us?)

5. The only divergence from black was when the Post WWII tubular steel post style was introduced where even on the short ground signals it was painted aluminium colour (and probably white in earlier schemes before aluminium was adopted) and aluminium was used on part of the balance weight lever as well - everything else was black.  However painting gang styles did vary a bit, for examples I have seen instances of the back of the cast disc painted in aluminium instead of black but it was unusual in my experience..

 6. In later years the back blinder was painted either white or aluminium but I don't know when that colouring was introduced and it might even have been in the 1907 S&T Painting Instructions (which I don't have immediately to hand, sorry) 

7. Balance weights always appear to have been black after the 'red lead' colour was replaced by black.

 

Mike's info is supported by the new "GWR Signalling Practice" book from the GWR Study Group.

 

1. Pages 70 and 71 show drawings and photos of the half disc ground signals with the rear side of the "disc" being white where not obscured by the mounting arm. 

2. Page 72 shows a photo of the back of a 15.5in ground disc. It's clear that the rear of this disc is white where it is not obscured by the scalloped triangular mounting (which looks like a very similar mounting to the one shown on the gwr.org.uk page for the "1918 tall pattern" ground disc). The caption for the photo says that, "the begrimed backshade is painted white so that it can be seen...". It looks "heavilly weathered" in the photo - you certainly wouldn't think it was white!

3. Two original Stores Dept. documents are reproduced in the appendices: "Double Disc & Fittings" and "Single Disc & Fittings" which both show fully circular mounting castings the same size as the discs they support.

6. See 2. The text implies that the backshade was painted white from the introduction of the 15.5in ground signal around 1915 - but that is not entirely clear.

 

@Junctionmad: The "Disc & Fittings" drawings are not for the tall pattern discs we've talked about but the exploded parts lists clearly show how that variant would have been constructed.

 

Edited August 31, 2019 by Harlequin

[Junctionmad]

 

Thanks everyone , illuminating as always 

 

looks like a book I should acquire 

 

what dd the support casting for the faceplate for the tall disk look like ? , it looks vaguely triangular from the bolt patterns 

 

Dave 

Edited September 1, 2019 by Junctionmad

[Harlequin]

4 hours ago, Junctionmad said:

 

what dd the support casting for the faceplate for the tall disk look like ? , it looks vaguely triangular from the bolt patterns 

 

Dave 

 

This is the outline from the drawing I sent you:

(Perhaps the top edge should be straighter...)

 

You can see it clearly on gwr.org.uk:

 

I'm not sure of the detail of the centre boss or the rear side, which I guess has some ribbing on it.

 

[Junctionmad]

thanks Phil , I remembered teh drawing after I posted 

[Tim V]

On 01/09/2019 at 07:05, Harlequin said:

 

This is the outline from the drawing I sent you:

 

(Perhaps the top edge should be straighter...)

 

You can see it clearly on gwr.org.uk:

 

 

I'm not sure of the detail of the centre boss or the rear side, which I guess has some ribbing on it.

 

 

My pictures! Full size here. This was at Lightmoor Junction, on the line going to Horsehay, September 1976. My friend is holding the tape at a certain distance - but I don't remember what that was ...

 

[Tim V]

Side view.

 

The other pictures were on my old website - the whole site had to be below 15mb, RMweb has a lot more space these days!

 

 

[Harlequin]

25 minutes ago, Tim V said:

 

My pictures! Full size here. This was at Lightmoor Junction, on the line going to Horsehay, September 1976. My friend is holding the tape at a certain distance - but I don't remember what that was ...

 

 

Wonderful! Thanks Tim - the extra detail and clarity will really help!

 

Edit: it would be great if gwr.org.uk showed these bigger pictures - and bigger pictures in general wherever possible.

 

Edited September 2, 2019 by Harlequin

[Junctionmad]

Brill 

 

Here’s my prototype all 3D printed 

( screen shot of a video ) 

 

needs a better paint job 

[Junctionmad]

Quick question , did BR ( WR) introduce the yellow on black permissive disc as I gather the gwr never used this type of disc 

 

if I wanted a dual route disc under a gwr era , I understand I could use a double disk or am I correct , I could use a white light in a stAndard red on white disk 

[The Stationmaster]

On 16/09/2019 at 20:48, Junctionmad said:

Quick question , did BR ( WR) introduce the yellow on black permissive disc as I gather the gwr never used this type of disc 

 

if I wanted a dual route disc under a gwr era , I understand I could use a double disk or am I correct , I could use a white light in a stAndard red on white disk 

The WR introduced the yellow on white disc in new work from January 1950 and they were probably used in some instances to replace siding signals simple as renewals.  I'm not sure when the change was made to yellow on black but think it was probably around the late 1950s, maybe even the early 1960s as I can remember yellow on white discs still being installed around then.  It generally seems to have been the case that yellow on black discs were substituted for existing yellow on white but only where teh smaller sixe was in use.  Earlier larger discs which had been repainted from red to yellow (on white) because no new enamel disc in that size was made remained as yellow on white well into the 1980s and probably lasted as long as the signal lasted (e.g. the example in the dairy sidings at Lostwithiel).

 

BTW these signals are not permissive.  They are an absolute stop signal when the points to which they apply are set towards a route to which the signal applies when it is off.

 

The GWR went to and fro between double, and in some cases triple, discs and single discs over the years.  the real decider is the date at which the signalling was installed or renewed at a particular place and whether or not there was considered to be a traffic need for multiple discs.  Changes in locking also had their effect as the use of white lights was actually driven by the inability to provide conditional locking in frames with double twist or stud frames - (G)WR white light discs were not directly comparable in application and usage with yellow arm discs . 

[bécasse]

8 hours ago, The Stationmaster said:

I'm not sure when the change was made to yellow on black but think it was probably around the late 1950s, maybe even the early 1960s as I can remember yellow on white discs still being installed around then.

The Southern Railway seems to have been the first to use yellow on black discs, although their use was limited to floodlit motor-worked round discs installed as part of colour light signal schemes starting, I think, with the ex-LSW main-line out of Waterloo in the late 1930s. Mechanically worked yellow ground signals on the SR continued to be miniature arms rather than discs (which the red ones were) until the late 1950s (probably 1958/59) when yellow on black discs started to appear instead. I have always assumed that this was the result of a BR edict which also outlawed the practice (not uncommon on the Southern) of discs permitting entry to a block section (other regions overcame the problem by providing an advanced starting signal). The discs concerned (which had often been elevated) were replaced by short-arm stop signals - resulting in the installation of a small number (perhaps a dozen) of yellow stop signals as well as rather more red ones. In most cases, the new signals had barely been installed before the yards concerned were eliminated!

[The Stationmaster]

14 hours ago, bécasse said:

The Southern Railway seems to have been the first to use yellow on black discs, although their use was limited to floodlit motor-worked round discs installed as part of colour light signal schemes starting, I think, with the ex-LSW main-line out of Waterloo in the late 1930s. Mechanically worked yellow ground signals on the SR continued to be miniature arms rather than discs (which the red ones were) until the late 1950s (probably 1958/59) when yellow on black discs started to appear instead. I have always assumed that this was the result of a BR edict which also outlawed the practice (not uncommon on the Southern) of discs permitting entry to a block section (other regions overcame the problem by providing an advanced starting signal). The discs concerned (which had often been elevated) were replaced by short-arm stop signals - resulting in the installation of a small number (perhaps a dozen) of yellow stop signals as well as rather more red ones. In most cases, the new signals had barely been installed before the yards concerned were eliminated!

Southern miniature yellow arm ground signals definitely lasted a lot than the late 1950s - there was still one in existence at a station on the Portsmouth Direct well into the 1970s.

[bécasse]

7 minutes ago, The Stationmaster said:

Southern miniature yellow arm ground signals definitely lasted a lot than the late 1950s - there was still one in existence at a station on the Portsmouth Direct well into the 1970s.

Indeed, with the exception of the installation of short-arm semaphores to replace dollies which could give direct access to block sections, the changes were only made on a renewal/resignalling basis, so the dates of introduction should be treated as "not before" dates. I have little doubt that the same applied on the WR.

[The Stationmaster]

1 hour ago, bécasse said:

Indeed, with the exception of the installation of short-arm semaphores to replace dollies which could give direct access to block sections, the changes were only made on a renewal/resignalling basis, so the dates of introduction should be treated as "not before" dates. I have little doubt that the same applied on the WR.

It did.  Backing Signals lasted (in diminishing numbers of course) into the 1980s although they became obsolete in 1950.  Similarly a few 1911 pattern ground discs lasted into the 1980s, including one which had the red band overpainted in yellow during the 1970s.

Edited September 19, 2019 by The Stationmaster