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Re: Setting of Points
Bernard Smith wrote:
> I have a question about the setting of points.
>
> Gordon station (NSW) has a terminating road that normally accepts Down
> trains so they can return to the City. This road can also be used for Up
> trains to terminate and return to Hornsby during trackwork and emergencies.
> Looks something like this.
>
> ---------------- Down
> --------------< >[a]----------->>>
> >------------[b]<
> <<<---------< >[c]-----------------
> Up ----------------
>
> For safe operation, the points at the Down end of the terminating road [b]
> can be * paired with the departure points onto the Down [a], * paired with
> the arrival points from the Up [c] or * 'paired' with both (and put in a
> split position if no movement is planned at the Down end).
>
> With a train arriving on the Up, and a train in the middle road, I noticed
> this morning that those points were set in the direction of the Up. That
> is, a Down terminator could end up heading wrong way on the Up if it failed
> to stop.
>
> I am sure that there is signal protection and a trip on the middle road, but
> why would those points be set so as to allow a head-on on the Up? A safer
> setting would be to set them to return a shootthrough to the Down.
When a train is arriving in the centre road on the down, the points are set for
an overrun onto the down track. So if the train fails to stop, it will safely
go straight back onto the down track. After a timeout proves it has stopped,
the points will then reverse allowing the following down train to pass. It is
not possible for the points to allow a conflicting movement until such time as
the train has been proved to be stationary.
--
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.