Re: Lightning Strike @ Dandenong

[Notagunzel <notagunzel@hotmail.com>]

Tony Gatt wrote:

> Richard Flinders wrote:
>
> > Anyone got any details?
>
> All that I know from this morning is that all signalling from Dandenong
> to Cranbourne has been knocked out. Trains have been replaced by buses.
>
> This is not the first time this has happened. The Cranbourne signalling
> is very prone to lightning strikes.
> If I were the PTC, I would be moving the control room :)

All the Signalling at Dandenong and down to Cranbourne hangs off the SSI at
Dandenong, with the field equipment communicating with the SSI via a trackside
data link.  The problem is, if the data link is damaged, all of the Signalling
fails.  With Relay interlocking, each location has its own relay room, with data
links used for control and indication only.  If the ATC to Cranbourne had been
done with small local single processor interlockings (eg Westrace or VPI) at each
location, the effects of lightning would be localized.  Even if the Remote
Control system was destroyed, local emergency keyswitches (like the Western CTC)
can be used to setup the local interlocking for the unaffected sections.  So
Caution Orders (verbally delivered) would only be used in the immediate vicinity
of the lightning strike.  I wonder how long it will take to  repair the fault,
considering the last time there was significant damage to the Signalling it took
several days to fix, with the dreaded busses used to ferry the suckers
(passengers) between Dandenong and Cranbourne.

BC