Re: Concord derailment

["Peter Knife" <pijik@knifecutt.fam.aust.com>]

All,

This discussion has triggered a recollection of an old rhyme that was
apparently drilled into people to help understand the NSW two-light signal
indications. In part, it went...

	"and if the yellow's down below, that means reduce to medium slow"

To me, that is an unambiguous indication, regardless of what the driver's
conditioned expectation might be. It holds the same force as the Y/G
indication in the VR (US) 'speed signalling' indications, which is a
warning that the next signal is displaying a medium speed indication. No
ambiguity.

I don't know if this is what actually happened (we'll all find out in due
course), but as far as the debate on ambiguity of indications, I don't
think there is any doubt on this one.

Peter Knife



Greg <gregz@tig.com.au> wrote in article
<357df97d.6145730@news.tig.com.au>...
> On Wed, 10 Jun 1998 05:30:28 +1000, "Ben Staples" <BenKim@bigpond.com>
> wrote:
> 
> >From what I know of signalling, If a driver of a passenger train
approaches
> >a medium caution (green over yellow) then he/she can travel past that
signal
> >at line speed i.e. it is treated as a proceed indictation (green over
> >green). Is this correct? 
> 
> yes you are correct,green over yellow is a medium caution
> idication,warning the driver that the next signl will be at caution,or
> in the case of an interlocking could show a turnout indication.
> 
> Though I presume that when approaching an
> >interlocking a driver make take extra care and drive for the slowest
> >possible route to be set. So, every time a train approcahes Concord West
and
> >the signal is at medium caution, does the driver have to slow down to
25km/h
> >just in case the road has been set to take the Up Sub. I wonder if there
is
> >enough distance to reduce your speed accordingly with the signal spacing
at
> >this point.
> 
> im no expert on train control although i keep out of trouble..there is
> ample distance to slow your train to 25kph for the turn out at concord
> west...
> but more to the point in the working timetable it shows an R at
> concord west meaning the train is tabled to run via the releif road
> for a rail clean..
> 
> 
> cheers greg
> >