Re: [SYD] Central Yard signal SY54

[Eddie Oliver <eoliver@efs.mq.edu.au>]

Maikha wrote

> > The signal was full red, but then the bottom light on SY54 had lit up
> > and the loco hauled train slowly moved out, on its way to Flemo.

> > Can anyone out there give abit of a word on this?

Presumably the "bottom light" you referred to was yellow, i.e. a "shunt"
light which authorises a train to pass the signal prepared to stop short
of any obstruction.

Signal-spotter wrote in response

> Could be a subsidiary shunt if it showed yellow or a Low Speed if it
> showed green, although the latter is generally mounted in the bottom
> head. 

The signal in question, like the other running signals in Sydney Yard
north of Cleveland St, is a single-light-indication type. As far as I
can recall on a quick mental scan, none of the single-light signals in
Sydney Yard are fitted with low speed indications.

Your generalisation re low speeds usually being mounted in the bottom
head (of double-light signals, presumably) is interesting, in that the
Strathfield/Lidcombe area is particularly rich in signals where the low
speed lights are on separate units rather than being the lowest light in
the lower main head. I don't know why - can anyone cast any light on
this (no pun intended)? One might theorise that they were designed to be
close-ups rather than low-speeds (and someone changed their mind in the
design stage) or maybe simply someone decided it was cheaper that way,
but does anyone know definitively?

Eddie