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NSWR Scattered Aces

Unread postPosted: Sun Jul 31, 2016 5:46 am
by stevej
I am curious to discover the origin of the NSWR single light turnout indicator, nicknamed the Scattered Aces. It was indicated by a slanted row of three subsidiary yellows positioned below the main signal head. The original single light turnout indicator being a large route indicator combined with a yellow main signal indication. The large route indicator was positioned above the main signal head, or for shunting and restricted speed, a small route indicator combined with a single subsidiary yellow indication.

I do recollect a circular for the implementation of the new single light turnout indicator for main line running, but, sadly cannot find that circular at home amongst my pile of safe working clutter.

The first application being combined with a yellow main signal indication. This reflected the Sydney Metrop colour light turnout indication given by top yellow. But, this was quickly altered to a red main signal indication after some misinterpretation incidents. Though utilized for main line turnout, such turnout speeds were normally slow, usually 25 kph.

A more recent alteration was the implementation of Medium indication by pulsating subsidiary yellows. Steady row of three yellows indicating the next signal is at stop, pulsating indicating the next signal is not at stop.
The Queensland Railway Junction Indicator (rabbit ears), being a slanted row of subsidiary lunar white lights may have been an influence. However, such rabbit ears were later adopted in NSW to act as a turnout repeater indication prior to the turnout signal. Or, did the NSWR signals branch adapt the Pennsylvanian Railroad Position Light signal type ?

In the photo, I am approaching signal D 90.2 Edgecombe UP home starter on the Down Main. ... sort=3&o=3

Having proceeded through the bi-directional running section between Zig Zag and Edgecombe, I will crossover to resume normal running on the UP Main. The main signal head is only capable of a red indication, as continuing in the wrong running direction is not possible under signals. Signal U 90.2 opposite is the Edgecombe UP Main home starter for normal running. The rear of signal 90.3 Down Home can be seen which also has a turnout indicator to permit crossover to the UP Main.


(Edited to correct link: SJ, moderator)

Re: NSWR Scattered Aces

Unread postPosted: Tue Aug 2, 2016 8:18 pm
It should be possible to work backwards to find out when the first 'scattered aces' was provided. I think once that date is established then things will become clearer.

Re: NSWR Scattered Aces

Unread postPosted: Thu Aug 4, 2016 5:43 am
by stevej
G'day MRFS,
I have been rummaging through weekly notices and circulars.
I am back to 1990 for implementation of scattered aces, but don't know if this is the earliest application here in NSW.
I do have a photo featuring an original single light turnout indication utilized, being a large route indicator above the signal, that I shot in 1990.
So, this may suggest that 1990 was the date for change to scattered aces.
But, I have no definite proof.
I shall keep searching.

Re: NSWR Scattered Aces

Unread postPosted: Sat Aug 6, 2016 1:56 pm
by Andrew Waugh
My history of the single light turnout indicator... Note that this is primarily from the GA and the rulebooks, which may have lagged behind what was actually happening on the ground. But note, my copies of the 1944 and 1966 GAs are fairly complete with amendments.

The amendment for automatic colour light signalling, single light indications was published in WN 43/58. It only shows three indications: stop, caution, and clear with a red, yellow, and green light above a lunar white marker light "visible during dark for identification."

The full single light indications were defined in Circular 1-1 issued by the CTM in January 1959, which included a coloured insert.

Turnout indications were defined as "The indication displayed for a turnout movement from the main line to a Refuge Loop or important siding consists of a band of lunar white lights [3 from the diagram] (inclined towards the direction of the movement) in a subsidiary light unit below a yellow light in the main line signal. The indication will be displayed only when the route is set for the turnout movement; at all other times the centre light of the band will remain illuminated to act as a marker light."

I would suggest the first examples would be on the blue mountains. The single light aspects were developed for that resignalling to reduce the signalling power supply required.

No further amendments existed in the 1944 book.

In the September 1967 GA the situation was more complex.

In Clause 6 (Crossing and Refuge Loop Signals), Clause c (Single Light indication), has the aspect altered to a band of yellow lights under a red main light. The indication was named "caution" and the meaning given was "Proceed cautiously into loop". The note clarifies that this was intended to give authority to enter running loops, although it was also used at "certain locations" as a turnout indication for a junction. However, an insert dated September 1967 shows the old aspects (yellow main light, lunar white band). The text says "The diagrams shown in the [GA] Part II in respect of the single light signal indications, illustrate signals with red marker light which is now the standard for single light indication signals. At earlier installations, lunar which marker lights are in use but these are being progressively changed to red marker lights and the indications displayed modified accordingly." The insert was to be retained in the GA until the WN notified that it could be discarded.

Note that the use of the inclined band of lights had been subtly restricted to only apply to the entry to a loop. For a diverging movement to a running line, the indication was "Caution turnout" and the aspect was a yellow main line aspect with a alphanumeric route indicator mounted above the signal head indicating the route. For movements into sidings, the indication was "Caution" with an aspect red/small red/small yellow. If there was more than one route a small stencil route indicator was provided adjacent to the yellow light.

There are no further amendments in the 1966 book.

The 1966 GA was replaced in March 1995 by a multivolume "plain english" version.

In this the various running turnout aspects were combined into one indication "Caution turnout" which was defined as "The next signal on the turnout route may be indicating stop. Proceed on the turnout route, prepared to stop at the next signal." The various aspects for this indication were:
* yellow main aspect with white band of lights (i.e. the original 1959 aspect to be removed in 1966!)
* red main aspect with yellow band of lights
* red main aspect with yellow band of lights and large route indicator above main aspect
* yellow main aspect with white marker and route indicator above main aspect
* yellow main aspect with route indicator above main aspect
I pity the poor drivers!

"Medium turnout" was defined as "The next signal on the turnout route is displaying a proceed indication. Proceed on the turnout route at normal turnout speed." The various aspects for this indication were:
* red main aspect with pulsating yellow band
* red main aspect with pulsating yellow band with route indicator above main aspect

After the Glenbrook accident (1999), the learned judge was quite rude about the 'clear english' of this rulebook, and it was extensively rewritten. These indications have been simplified; Caution Turnout is now only red over yellow band (in single light territory), and Medium Turnout red over pulsating yellow band. I think either can have a route indicator.

So this suggests:
* The turnout indicator was introduced in 1959 with white lights under a yellow main line aspect for moves into a loop or important siding
* Probably in 1966 the turnout indicator was restricted to moves into loops, and was altered to yellow lights under a red main line aspect. New aspects were introduced for running diverging moves (route indicator over a yellow main line aspect), and shunting moves (red/red/yellow with small route indicator if more than one route). The old aspects still existed, but were supposed to being phased out.
* Probably in 1995 the various running turnout aspects were unified into one indication (Caution Turnout). Certainly by this time the turnout indicator could be used for main line crossovers. By this time the pulsating band for Medium Turnout had been introduced.

Re: NSWR Scattered Aces

Unread postPosted: Sun Aug 7, 2016 6:03 am
by stevej
G'day Andrew,
You have included a wealth of information that I will need to digest at home.
Yes, I possess the 1995 circular when pulsating yellow indications were implemented.
Yes, the scattered aces and prior use of a large route indicator above a main yellow were intended for main line diversion movements, not for sidings or yards.
A large route indicator now used with scattered aces when more than one main line diversion is possible.
I have now seen reference to upper quadrant semaphores with the "junction" indicator (scattered aces).
But, I have never witnessed such usage.
I have also found a circular featuring Goulburn in 1979 which seems to feature the scattered aces.
Though the image quality is poor when zoomed in.
The concept has probably been around for many years, but only gradually implemented.
Now that I have seen reference with upper quads, I am kinda thinking that as our upper quads were USRR based, so mayde the scattered aces be also.
I shall digest your information at home.
Steve. ... sort=3&o=1