Re: Signaller causes SPAD

["B." <gunzel412@dingoblue.gunzel.net.au>]

David Johnson <trainman@ozemail.com.au> wrote in message
39CB1271.86E2738@ozemail.com.au">news:39CB1271.86E2738@ozemail.com.au...
> signal_spotter@my-deja.com wrote:

>> Apparently there was a near incident where a train nearly
>> hit a loco. The reason was that the loco derailed and came
>> completely off the tracks and therefore the track circuit
>> picked back up. He was telling me that I should design
>> into the system the ability to detect a train when it runs
>> off the track.

> It is possible with sequential clearing.  I think Cowan has
> it, moreso not to lose trains due to sand on the track
> rather than derailment.

ISTR this has been discussed before.

Sequential proving of tracks isn't common in Australia, but I seem to
remember that QR uses some sequential logic in it's UTC software, so if any
irregular track circuit operation occurs, an alarm is generated for the
controller.

There is also another NSW signalling installation (in the Hunter Valley?)
that has sequential operation of some sort.

In Victoria the only thing that comes near it is the trap tracks at tramway
squares, as there isn't any track circuit through the H crossing itself.

Sequential operation of track circuits is used alot more in Europe, where
their signal relays don't use silver to graphite contacts.  So they like
proving absolutely all relay operation.

--
B.

Email - gunzel412 at dingoblue dot net dot au
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