Re: Simple Question.....

["David Proctor" <daproc@bigfoot.com>]

Simple really - although complicated if you do not know (I presume you are
talking about NSW safeworking here)

The top light is the authority to enter the next section - Red = stop,
Yellow = turnout, Green = go

The bottom light gives an indication of the signals in advance.

Thus, 2 Reds indicates stop, this will be preceded by a Green over Red,
which will be preceded by a Green over Yellow, which will be preceded by a
Green over Green - thus, a driver will get at least two signals advance
warning of a signal being at stop.

There are variations on this, with some other peculiarities thrown in,
(such as Close-Up and low-speed signals) but the principle is basically the
same.

Hope the above is of assistance.


-- 
Regards

David Proctor
daproc@bigfoot.com

David Bradshaw <dab@sydney.dialix.com.au> wrote in article
<883539593.340513@fermi.dialix.com.au>...
> Just a simple question from an inquisitive commuter:
> 
> Often I see two sets of lights one atop the other (ie on the same post). 
> I gather (correct me if I'm wrong here) that red = stop; amber=proceed 
> with caution; green = proceed, though I am a bit lost as to the role of 
> the dual signals!!
> 
> David Bradshaw
> 
>