Modelling SR Westinghouse half-disc ground signals

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stephenfreeman
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Re: Modelling SR Westinghouse half-disc ground signals

Postby stephenfreeman » Sat Jul 03, 2021 12:26 pm

Whilst I don't have a current need for any more of them, I am eternally grateful for Dougs solution to make the disc work as it can equally well be used for other Discs that have the same issue and has also been explained adapted to work the balance weight arm as well.

As an aside what do people think of the Scalelink discs that are on their etch of Southern Arms? They seem a little on the large side when compared to others but given their provenance are they right and others wrong?

bécasse
Posts: 377
Joined: Sun Jun 17, 2018 8:26 am

Re: Modelling SR Westinghouse half-disc ground signals

Postby bécasse » Sat Jul 03, 2021 1:38 pm

stephenfreeman wrote:Whilst I don't have a current need for any more of them, I am eternally grateful for Dougs solution to make the disc work as it can equally well be used for other Discs that have the same issue and has also been explained adapted to work the balance weight arm as well.

As an aside what do people think of the Scalelink discs that are on their etch of Southern Arms? They seem a little on the large side when compared to others but given their provenance are they right and others wrong?


I will leave you to check the model dimensions :-
SRsigsDwg2.jpg
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stephenfreeman
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Re: Modelling SR Westinghouse half-disc ground signals

Postby stephenfreeman » Mon Jul 05, 2021 8:52 am

Most useful, thanks. Appears to confirm what I thought, Wizard is pretty well there, Scalelink are oversize (unless the Southern have a larger size I don't know about).

bécasse
Posts: 377
Joined: Sun Jun 17, 2018 8:26 am

Re: Modelling SR Westinghouse half-disc ground signals

Postby bécasse » Mon Jul 05, 2021 12:04 pm

stephenfreeman wrote:Most useful, thanks. Appears to confirm what I thought, Wizard is pretty well there, Scalelink are oversize (unless the Southern have a larger size I don't know about).


No, they don't. Originally the "red" shunt dollies used red/white arms the same size as the yellow/black ones drawn above the disc in my drawing but at the end of the 1920s the white/red discs were introduced instead gradually replacing the arms. The yellow/black arms were introduced at that same time (late 1920s) until they too were replaced by black/yellow discs towards the end of the 1950s (although most installations became redundant before the discs could be substituted and a few sites where the signal led directly into a block section gained full-size signals with subsidiary yellow/black arms).

The situation at Southern colour light installations was different, the earlier installations used two-aspect (R/G or Y/G) - or very rarely four-aspect (R/G|Y/G or Y/G|R/G) - miniature colour light signals, and these remained until the installations were replaced, typically in the 1970s or 1980s. However, from the late-1930s floodlit motor-operated ROUND discs were used instead, mainly white/red but with a few black/yellow, and these continued to be installed until the late 1950s when miniature position-light signals started to be used instead; calling-on signals during this period were also floodlit motor-operated round discs with a large C on them.


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