Re: New questions for rail experts

[signal_spotter@my-deja.com]

In article <392BEEDC.F74ECB68@ozemail.com.au>,
  trainman@ozemail.com.au wrote:
> Dave Proctor wrote:
>
> > In NSW, they leave the trips at the end of the train down, so that
it is
> > down on the front AND the back of the train. In Victoria, I believe
they
> > raise the trip at the back and then lower the trip at the other end.
> >
> > Not sure as to how they work the arrangement of the trip on the back
> > carriage hitting a train stop when running on a line signalled for
> > bi-directional running. I have seen some trips lower when a train
is to run
> > in the opposite direction, I have also seen the back trip strike a
train
> > stop and not be braked (presumably, it only works when the lever on
it moves
> > in the one direction).
>
> The trips for rear facing signals are suppresed when the road is set
in the
> opposite direction.  This means they are kept lowered.  A trip
hitting a train
> stop in the wrong direction will not cause it to trip, however, if
the train is
> travelling fast enough (above about 40 km/h) the trip will bounce
back and
> operate itself.
>
> It is worth mentioning that unless the trip arm is lowered, the train
will not
> power.
>
> --
> David Johnson
> trainman@ozemail.com.au
> http://www.ozemail.com.au/~trainman/
> ------------------------------------
> These comments are made in a private
> capacity and do not represent the
> official view of State Rail.
> C.O.W.S. Page 11.
>

Ahhh trainstop suppression. I tell ya that gave me a few headaches the
day after we commissioned the Dapto trainstop job just before
christmas. They had a failure the next morning and I was called out to
fix it at 6 the next morning. Anyway one of the problems was that the
trainstop wouldn't suppress for the opposite direction moves and I saw
a few trains backtrip at about 60 kph. All that happened was the trip
hit the back of the arm and then return. I was hoping (praying) that it
didn't break the trainstop arm which can happen. So it's all fixed now.
Anyway getting back to the subject, yep trainstops are suppressed for
opposite direction moves. The suppression is instigated by the clearing
of the signal (except SSI where we suppress it with the route memory)
and is held by the track circuits between the signal and the trainstop
occupied. Suppressed trainstops are not detected reverse in the signal
that suppresses them. The same phylosophy is used to suppress AWS
magnets in QLD and UK signalling systems. Anyway hope this helps.

regards

Ian Hayes
Signal Design Engineer
>


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