> CityRail is currently upgrading the signalling on Wynyard Platform 4
> and is installing additional new "speed signalling" train stops along
> the platform. There is a grey, sort of triangular shaped, box mounted
> between the rail near, but not necessarily immediately adjacent to,
> each train stop and just clear of the rail on the train stop side.
> The grey box is connected into the signalling system wiring. The
> boxes seem to be only associated with intermediate train stops, not
> the train stops at signals.
>
> I notice the these boxes are also installed in similar fashion at
> Martin Place,
>
> What is the purpose of these boxes.
They detect the presence of a train, I think via an induction loop, but I'm not
sure. This starts a timer to lower the trip. If the train is going too fast,
it gets to the trip before it goes down.
I'm pretty sure this is how they work, but I would appreciate confirmation from
a sig elec.
-- David Johnson CityRail Guard trainman@ozemail.com.au http://www.ozemail.com.au/~trainman/