Reuse of old signal arms?

Any aspect related to the structures and equipment on the Caledonian Railway Company.
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John Lindsay
Posts: 107
Joined: Mon Aug 27, 2012 10:28 am

Reuse of old signal arms?

Post by John Lindsay »

Hi all

Whilst looking at some of the photos I have of Biggar Station the other day, I noted that the arm of the Up Starter Signal was changed at some time between 1906 and 1935 (ish). Not in itself surprising, but the replacement arm (see the right hand of the two photos) appears to be of the design used earlier than the one it replaced. Would anyone care to hazard a guess if this would have been a old stock item from many years before or a import from elsewhere on the LMS system?

Thanks

John
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Jim Summers
Posts: 1000
Joined: Tue Aug 14, 2012 8:54 pm

Re: Reuse of old signal arms?

Post by Jim Summers »

John,
The one on the right is the Stevens teardrop design, which David Stirling opines ceased to be used around 1905, when the Caley started producing their own arms. I have a note (reproduced on p100 of Signalling the Caledonian Railway) which says that rare examples of the older style could be seen into the 1950s.

It would be surprising if one of the older style replaced one of the Caley's more recent own style, but Signalling fitters had to be resourceful at times, so it is not impossible.

JimS
dunalastairv
Posts: 262
Joined: Wed Dec 12, 2012 7:01 am

Re: Reuse of old signal arms?

Post by dunalastairv »

I'm lucky enough to own examples of both the 'teardrop' design and the later Caley standard pattern: both have spindles of pretty well the same diameter - about 1 3/16" - so it would be perfectly possible to substitute one type for the other without changing the spindle casting. There's also no reason why this wouldn't be done on lines where economy was already the watchword by the 1930s, especially if the coloured shades were not broken. I accept it's probably unusual but perfectly feasible.
Mike 1
Posts: 70
Joined: Tue Feb 12, 2019 8:46 pm

Re: Reuse of old signal arms?

Post by Mike 1 »

At Aylesbury LNWR station there was a lamp room where handlamps were kept and signal lamps were tended to. They also kept a spare spectacle plate so that storm damage could be repaired on site, though they didn't for some reason keep a complete arm. This lasted into the 1960s when the line was closed. I guess Caledonian policy would be similar and maybe they just kept one spare for all the signals at the station and they might not have been all the same type?

Mike
dunalastairv
Posts: 262
Joined: Wed Dec 12, 2012 7:01 am

Re: Reuse of old signal arms?

Post by dunalastairv »

I'm afraid there's a problem with that theory - the two types of spectacle were not interchangeable as the fixings were different. That doesn't matter as far as the pivot spindles are concerned but it does if you want to change the spectacle castings. I could, however, believe that the local Signal Dept kept stocks of arms and spectacle assemblies complete.
John Lindsay
Posts: 107
Joined: Mon Aug 27, 2012 10:28 am

Re: Reuse of old signal arms?

Post by John Lindsay »

As an additional thought - would the angle through which the arm moved have been different? The original arm drops a long way, but the angle between the two lenses in the latter replacement looks less.

Cheers

John
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