Re: Double Colour Light Signalling

[billbolton@REMOVE-TO-EMAILacslink.net.au (Bill Bolton)]

Michael Cuthbert <mcuth@sydney.nospam.dialix.oz.au> wrote:

> 3) North Shore Line (NSW) signalling. I've noticed that some of the
> signals are missing the "caution" aspect (Green/Yellow), 

More than, "some"... "most" would be more appropriate

> progressing from R/R, G/R, G/G. Why is this so on a pretty heavily used
> track? An anti-blocking measure?

The parts where traffic tends to bunch up, such as heavy grades south
from St Leonards and at the North end, tend to have four aspect
signals while the rest of the Shore tends to have three aspect
signals.  Even allowing for peak hour traffic with express services
form the Central Coast, service density of the Shore under normal
circumstance is such that minimum headways are still 2 to 3 minutes at
most locations.

Cheers,

Bill
  
Bill Bolton
Sydney, Australia