Stacked shunt discs.... or not?

[Titanius Anglesmith]

Greetings All,

 

I'm sure this has been discussed before but I just cannot find it. I must be searching for the wrong terms. I have a few questions regarding stacked shunt signals for multiple routes please, if I may?

 

1. When did they come into use, and in what regions / companies? I'm aware that the LMS were quite fond of them, but was that an LMS innovation or inherited from pre-grouping?

 

2. What arrangement was in place before stacked discs came into use?

 

I realise that I'm asking two very big questions there with lots or permutations. For what it's worth, I'm interested mainly in LMS and Midland practice (and even that's a big ask.....)

 

Thanks in advance

[RLWP]

Does this help?:

 

Richard

[Titanius Anglesmith]

Thanks for the link, RLWP. It doesn’t really address my questions, but very interesting nonetheless. I’m intrigued that the LNWR didn’t adopt miniature arm shunts until 1915, I thought it was much earlier than that. My local railway also used miniature arms; they were absorbed by the Midland and then the LMS, but some of the arms survived until colour light signalling arrived in the ‘60s. It’s something I’m tempted to model instead of the more usual discs. 

[Joseph_Pestell]

I can't reply as regards other companies. But the Midland/LMS certainly made plenty of use of them. The only snag is that while you can just about get away with modelling shunting discs non-operational in the smaller scales, miniature signals need to be made to work - which is fiddly, especially when stacked three high.

 

Graham Warburton produced a fairly definitive book on LMS signals (as well as a series of articles in RM) in the late 70s (?). If you can find a copy of that, you should be well on your way.

 

Edit: A quick Google has found that it was reprinted in 2010 as a paperback by Crecy Publishing. ISBN9781906419417. £14.95 and still in print.

Edited June 27, 2019 by Joseph_Pestell
Add info

[RLWP]

2 hours ago, Titanius Anglesmith said:

Thanks for the link, RLWP. It doesn’t really address my questions, but very interesting nonetheless.

 

So we are talking about stacked ground signals, not the short armed signals found in goods yards?

 

Richard

[RLWP]

1 minute ago, RLWP said:

 

So we are talking about stacked ground signals, not the short armed signals found in goods yards?

 

The LNWR used rotating lamp signals from 1881 before the introduction of the miniature arm ones. Both were later adapted to take discs

 

Richard

[RLWP]

From here: http://www.derby-signalling.org.uk/Midland.htm

 

Quote

The Midland made relatively little use of shunting signals or ground discs, and did without them at locations where other companies normally provided them – as, for example, to govern setting back movements into a platform. London Road Junction, Derby, for instance, had no shunting signals for a set-back from the south, although this was a very common movement; there were, however, signals for a set-back from the west, and I had been told that these were only provided after an accident when a man going over the sleeper crossing there at night had with him a bicycle, whose green sidelight was mistaken for a shunter’s hand signal.

 

So it sounds like your example has been resignalled by the LMS

 

Richard

[Titanius Anglesmith]

26 minutes ago, RLWP said:

 

So we are talking about stacked ground signals, not the short armed signals found in goods yards?

 

Richard

 

Please forgive my ignorance, but what is the difference? I think we may have our wires crossed.

 

5 minutes ago, RLWP said:

From here: http://www.derby-signalling.org.uk/Midland.htm

 

 

So it sounds like your example has been resignalled by the LMS

 

Richard

 

My local railway is the LT&SR. Their short / miniature shunt arms were certainly installed by the LT&SR when they were still an independent company. Some locations were later resignalled by the LMS and received discs. 

 

In in any case, your quote regarding Midland practice is most interesting, and I think answers my original question. Thank you for that 

[RLWP]

You seem to be using several descriptions for something that could refer to entirely different things

 

Some signals had short arms - shunt signals for instance, and weer fitted to 'standard' posts and brackets

 

Ground signals sometimes had miniature arms and could be stacked

 

I'm checking you are talking about miniature arm stacked ground signals, like the LNWR ones?

 

Richard

 

 

[Gordon A]

I believe stacked shunt discs were also used by the GWR.

 

Gordon A

[Titanius Anglesmith]

2 hours ago, RLWP said:

You seem to be using several descriptions for something that could refer to entirely different things

 

Some signals had short arms - shunt signals for instance, and weer fitted to 'standard' posts and brackets

 

Ground signals sometimes had miniature arms and could be stacked

 

I'm checking you are talking about miniature arm stacked ground signals, like the LNWR ones?

 

Richard

 

 

 

My apologies for the confusion. I am referring to the ground signals (disc or  miniature arm) used for shunt moves to / from goods yards etc. 

[RLWP]

7 minutes ago, Titanius Anglesmith said:

 

My apologies for the confusion. I am referring to the ground signals (disc or  miniature arm) used for shunt moves to / from goods yards etc. 

 

Cool, I guessed that's what you were talking about

 

We now need someone with more experience of signalling to give a proper answer - we've reached the end of my knowledge and googling...

 

I'd still like to find a picture on line of the LNWR shunt signals from 1910. The arms were about two foot long, there was a stack of four of these on a post at Heaton Norris (Pictorial Record of LNWR Signalling, page 96, plate 7.11). They are incredibly cute*

 

Richard

 

*That's my credibility blown

[bécasse]

My recollection, and I could be wrong, is that the standard LMS disc signal only came as a single or a double, and that if there were more signalled routes than two the ex-LNWR design with miniature arms (which in theory could be stacked as high as needed) was used instead - as at Heaton Norris.

[The Stationmaster]

21 minutes ago, bécasse said:

My recollection, and I could be wrong, is that the standard LMS disc signal only came as a single or a double, and that if there were more signalled routes than two the ex-LNWR design with miniature arms (which in theory could be stacked as high as needed) was used instead - as at Heaton Norris.

No. the standard LMS disc  signal definitely came as a triple if required (I have a photo of one) but I'm b not sure without checking if thee maximum permitted number of arms (i.e. discs) was three or four - I think three but would need to check.  The GWR also had a standard casting for mounting three discs and there was still a brand new one sitting in Reading Signal Works stores in 1979 - long after such things were obsolescent.  The GWR also had a two arm ground signal prior to 1919 but I have the impression that they weren't widely used as I've not come across any photos of them in situ.

 

Alas I can't help much on LMS group companies beyond sayin the LNWR used two patterns of ground signal - one was a rotating version which was possibly not an independent signal and the other, much more commonly found, was a  miniature semaphore signal (as was the GWR independet ground signal prior to 1911.  The Midland used a ground disc with a sort of 'half disc style' for independent ground signals.

 

So going back to the OP and looking at the ex LNWR side of the LMS there were two types of ground shunting signal as I've c described above and the miniature semaphore stuyle could come with two arms but that might have been a post-group modification.  The LMS used stacked discs up to definitely three arms (i.e. discs) but for signalling more routes when reading out of sidings etc they used the standard short arm semaphore with the arms arranged one above the other, as per the crexamp,e at Heaton Norris by the sound of your description..

[jonny777]

There appears to be a short section on the subject here, 

 

https://www.igg.org.uk/gansg/3-sigs/gndsigs.htm

 

[Flying Pig]

42 minutes ago, The Stationmaster said:

No. the standard LMS disc  signal definitely came as a triple if required (I have a photo of one) but I'm b not sure without checking if thee maximum permitted number of arms (i.e. discs) was three or four

 

There was a well known four-disc example at Forders Sidings (LMS installation on an ex-LNWR line), but the caption on the linked page indicates it dates from 1972, well after Nationalisation.  This photo shows that there was previously a single disc at the same location.

[Titanius Anglesmith]

24 minutes ago, Flying Pig said:

 

There was a well known four-disc example at Forders Sidings (LMS installation on an ex-LNWR line), but the caption on the linked page indicates it dates from 1972, well after Nationalisation.  This photo shows that there was previously a single disc at the same location.

 

Which begs the question, how did the lever for the single disc interact with the rest of the frame? Did it lock the relevant points both ways?

 

Very interesting, thanks for the info everyone

[Grovenor]

54 minutes ago, Titanius Anglesmith said:

 

Which begs the question, how did the lever for the single disc interact with the rest of the frame? Did it lock the relevant points both ways?

 

Very interesting, thanks for the info everyone

Yes it would lock the points both ways so the points could not be moved with the signal clear. Selection over point detection could not be relied on for point locking.

[bécasse]

19 hours ago, bécasse said:

My recollection, and I could be wrong, is that the standard LMS disc signal only came as a single or a double, and that if there were more signalled routes than two the ex-LNWR design with miniature arms (which in theory could be stacked as high as needed) was used instead - as at Heaton Norris.

Ironically, I had only written this a few hours before I came across a photo of a three-stacker (in the current issue of Railway Bylines). The discs are, incidentally, quite significantly overlapped with only the top one fully visible.

[The Stationmaster]

16 hours ago, Titanius Anglesmith said:

 

Which begs the question, how did the lever for the single disc interact with the rest of the frame? Did it lock the relevant points both ways?

 

Very interesting, thanks for the info everyone

It depends entirely on the interlocking system in use and what movements had been required to be signalled when teh framne was specified and designed.  For example in some cases on the GWR/WR the disc would be released by the point lever standing reverse and would accordingly backlock the point lever when the ground disc lever was reversed.  In later years when either way locking was available the arrangement would be for the point lever to release the ground disc lever from either position and the disc's lever would backlock the point lever in either position  when it was reversed.  It really came down to the type/design of the interlocking and what had been operationally specified but as a general rule in many instances a movement past a ground signal standing at danger (because it couldn't be lowered) meant the points were not locked.

 

Plenty of lever frames went to the great signalbox in the sky (aka melting shop) with disc levers released by point levers standing reverse and no sort of locking if the disc was passed in the 'on' position when the points were standing normal.   I remember that on the WR we had to do a survey for all the 'boxes on our patch c.1975/76 of the number of ground discs which had to be passed at danger for regular movements and which meant the points were not locked.  At one of my 'boxes we were making an average of c.30 movements a day over one point end where that was happening (a consequence of very changed traffic patterns since the frame had been installed in the late 1940s).   No alterations were ever made to the locking and it remained unchamged inunti,  the 'box was closed in the 1980s.

[Grovenor]

16 hours ago, Grovenor said:

Yes it would lock the points both ways so the points could not be moved with the signal clear. Selection over point detection could not be relied on for point locking.

Looks like I misunderstood the question, my answer related to the two disks with the same lever no. As SM says with a single disc it all depends on circumstances, in the case at question with 4 routes and assuming the disc could be cleared for any route then the relevant points would be locked as required for each route which would involve at least one set being locked both ways. As this was a red disc and not GWR it should not be passed at danger, that would require a yellow disc in that time period.

[beast66606]

A (once) 5 stack at Hooton (South) in 1979

[LNERGE]

There was a stacked disc at Sandy. This is not it but one i made earlier..

 

 

[LNERGE]

On 29/06/2019 at 12:00, beast66606 said:

A (once) 5 stack at Hooton (South) in 1979

Was some expecting a Cartic4?