Re: Signalling in Victoria

[David Langley <del@ancc.com.au>]

Christopher_Martin GORDON wrote:

> Can someone explain the operation of 'speed' trips please.
>
> I mean where you pass one signal at say Red over Yellow and then there
> are 3 or 4 trip levers before the next signal (red over red) and they
> drop at a certian time so if the train is going too fast it is stoped
> before the signal.  Thats what I think.

Trip arms are provided to stop trains if they pass a signal at the stop
position but then you are aware of that. They are also used to enforce the
requirement of a train to maintain a low speed when entering certain tracks as
you note in the Melbourne Underground they are also provided in the Sydney
Underground at stations. There was also an intermediate trip between Chatham
and Canterbury in advance of the signal protecting the gates at Canterbury.

The intermediate trips are time delayed and lower after a certain time has
elapsed following the occupation of the platform track circuit. If the train
is travelling too fast then it will be tripped. The one at Canterbury was
provided for the same sort of reason except it was because the trains were
descending a fairly steep grade. If a driver lost control, the train would
trip at the signal protecting the gates but would not stop until after it had
smashed its way through the gates and into busy Canterbury Road. Yes it was
even busy in those days. This was all removed when grade separation of the up
line took place on 15 September 1968.

>
>
> They are in the city loop, Spencer Street, Flinders Street, anywhere else?

Keep a look out.

>
>
> They will be installing them at Ringwood (No. 2 road was marked today)
>
> One more interesting thing at Ringwood, for the new set up, the last home
> signal on the Up Belgrave Line before the down end points will show the
> following:
> Top light Red/Yellow/Green
> Bottom Light  Red/??????
> and a low speed light.
>
> What would the other colour be on the bottom light?
>
> There are two possible routes from this signal (once working) to No 2
> road, or the new platform 1 (which requires a diverge through the single
> compound)
>
> I would say the diverge would be Medium Speed, and the straight normal
> speed.  If the bottom light was yellow, then it would work, if the bottom
> light was green then you could show reduce to medium speed.

Yes medium speed. Either yellow or green. If the road is set into the platform
but not out at the up end, then I would expect R/Y but if the departure signal
is also cleared then I would expect R/G.

David Langley.