"Small Yellow Aspect"

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"Small Yellow Aspect" 08/01/2014 at 00:43 #53656
thecabbagedetective
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14 posts 		Hi, I was hoping someone with a bit more signalling knowledge than me could help out. At the address below is a file which was published when multi-aspect signalling was introduced in the Plymouth area, in the file it shows signals P47, P49, P51, P53 and P57 which is located on one end of the Plymouth platform area. The way I understand these signals are designed so that it has a route indicator which can be used with the main aspect or shunt signal to allow the train to move/shunt onto the up/down main line, and there is a "small yellow aspect" with it's own route indicator which is used when the route is set to either of the engine lines. What I don't understand is why would the signal be designed with the extra route indicator, instead of the small yellow aspect and it's own route indicator, why not just use the shunt signal and set the main route indicator to S1/S2?

Many thanks in advance.

The file is located here:
http://www.s-r-s.org.uk/ArchiveSignals/brwr.php#plymouth - (click on the link titled B1165 1960)

Shaun
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"Small Yellow Aspect" 08/01/2014 at 06:46 #53659
Peter Bennet
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5362 posts 		I don't know the reason but it sounds very much like what they have at Perth for trains running into the Cartridge Sidings. I've represented them by colouring the PL Yellow for the relevant routes.

Peter
I identify as half man half biscuit - crumbs!
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"Small Yellow Aspect" 08/01/2014 at 09:50 #53661
Forest Pines
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525 posts 		They are an additional type of subsidiary signal which is no longer used. My understanding is that at the time they were installed, the "cat's eyes" two white lights aspect was only used as a subsidiary for calling on moves into occupied roads or moves up to a shunt signal or LOS, and the small yellow aspect was used for moves into yards where the line may or may not be occupied (and where different rules apply compared to running lines).

However I am sure someone who's more of an expert than me will be able to confirm or correct the above!
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The following user said thank you: thecabbagedetective
"Small Yellow Aspect" 08/01/2014 at 11:43 #53663
thecabbagedetective
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14 posts 		Thanks everyone for your help, they have been removed from the platform area anyway since.
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"Small Yellow Aspect" 08/01/2014 at 12:38 #53664
TomOF
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452 posts 		I think Glasgow Central had these at some point too.
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"Small Yellow Aspect" 08/01/2014 at 19:32 #53682
Ron_J
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329 posts 		They are called "miniature yellow" aspects. Forest Pines' post has explained their function pretty well. Perth is now the only location on the entire national network still equipped with miniature yellows and all but one of them are signed out of use. The only working one is that associated with P46. I've uploaded a couple of photos of it here. It's interesting to note that MY aspects are not defined or explained in the Rule Book or Scotland Route Sectional Appendix so traincrews encountering P46 for the first time have no official guidance on what it means!
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The following user said thank you: GoochyB
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