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Re: Setting of Points
<signal_spotter@my-deja.com> wrote in message
8qp1vg$6cm$1@nnrp1.deja.com">news:8qp1vg$6cm$1@nnrp1.deja.com...
> In article <ikHz5.58120$c5.160289@newsfeeds.bigpond.com>,
> "Bernard Smith" <epping.smiths@gatewaynet.bigpond.com> wrote:
> > I have a question about the setting of points.
> >
> > <snip>
> >
> > Looks something like this.
> >
> > ---------------- Down
> > --------------< >[a]----------->>>
> > >------------[b]<
> > <<<---------< >[c]-----------------
> > Up ----------------
> >
> > <snip>>
> >
> >
> Well Bernard, I designed the signalling interlocking at Gordon (and
> Lindfield and the auto sections from Nth Syd to Waitara) when I was
> with State Rail so hopefully I can answer your query. With facing
> points, they are not normally set normal unless there is a conflicting
> move set or a track occupied in the overlap or no valid overlap
> available through the points reverse or there is a set of trailing
> points locked reverse in the facing points reverse overlap. So even
> though the overlap was set to the Up main, if the route was set it
> would have set those points normal (and locked them). As a last line of
> defence the track circuits would have held the aspect to red as well.
I guess my question boils down to something like "If you are going to have
conflicting settings, wouldn't it be better to have the trains heading in
the
same direction."
With a train in the middle road, this is true at the City end, but not the
Pymble end (albeit no movement is expected there). What happens if
a train comes to a rest and then continues northbound?!?
Another test is whether the opposite settings apply when trains terminate
from the North. Do the city end middle points face the Up until the train
comes to a stop and then face the Down (allowing a train to move wrong
way on the Down after stopping)?