Re: Crossing loop design (r.e. Southern Aurora crash)

[David Johnson <trainman@ozemail.com.au>]

MarkBau1 wrote:

> The whole mess could be resolved by simply going back to the way Vic 3 pos.
> signals were supposed to work in the first place.
>
> Top light for the straight road, bottom light for the divering road.
>  So, at our Western line CTC loops we'd simply get a Y/G at the last auto
> before the loop, (have to make sure it was far enough away from the loop) and a
> R/Y on the home arrival.
>
> If on the straight you'd get a Y/R on the auto and another Y/R on the home
> arrival. (In most cases it would not do to go from G/R on the auto to a top
> yellow on the arrival due to braking distances.
>
> Hopefully down the road if a US outfit gets V/Line they will convert to
> standard US signalling practice which is what the VR system was supposed to be
> in the first place.

Sounds confusing as hell to me.  I put my vote with the NSW system - very easy to
read.  The top light tells you what to do at THAT signal.  If it is Red, you stop.
If it is Green, you go.  If it is Yellow, you turnout.  Simple, eh?   The bottom
light basically tells you what the top light will be on the next signal.  If it is
Red, the top light of the next signal will be red.  If it is Green, the top light
of the next signal will be green.  All new SSI interlocking are being fitted with a
wonderful new system:  If the signal before a home has a bottom yellow, the Home
will be a turnout.  All other signals with a bottom yellow means the next signal
will be a green over red.

This is just a very basic rule of thumb, but works in most cases.  It is far easier
to understand than Victoria or USA signalling.  Whenever I play one of the USA
driving simulators I am forever referring to a page full of signal indications to
see what speed I can do, etc.

In NSW, the only indications you will get on the main line are:
G/G (Full Clear)
G/Y (Medium)
G/R (Caution)
R/R (Stop)
R/R/G (Low Speed)
R/R/Y (Shunting Signal)

Y/Y (Turnout)
Y/R (Turnout Caution)

Would someone like to post the complete list from other places?

BTW - QR gets my second vote - they are easy to understand too.

--
David Johnson
CityRail Guard
trainman@ozemail.com.au
http://www.ozemail.com.au/~trainman/