Re: Brief Signalling failure at Camberwell

["B." <b.spammed@four12.net>]

"Mark Bau" <markbau@earthlink.net> wrote in message
B6FA878F.2241%markbau@earthlink.net">news:B6FA878F.2241%markbau@earthlink.net...
> in article 3ad522e7$0$25508$7f31c96c@news01.syd.optusnet.com.au, Michael
> Wierzbinski at wizzer1865@NOSPAMoptusnet.com.au wrote on 4/11/01 9:26 PM:
>> "Sam Eades" <seades@bigpond.net.au> wrote in message
>> 11cA6.529$wP3.3566@news-server.bigpond.net.au">news:11cA6.529$wP3.3566@news-server.bigpond.net.au...
>>> "Paul Hambleton" <phambleton@labyrinth.net.au> wrote in message
>>> fnaA6.12$Z53.2560@vic.nntp.telstra.net">news:fnaA6.12$Z53.2560@vic.nntp.telstra.net...

>>>> A bit of excitement this morning at Camberwell.
>>>> As the 1023 UP from Alamein approached platform 2, all the signals
>>>> went out.  No lights whatsoever. The driver dutifully stopped at the
>>>> automatic signal guarding entry into platform 2 before proceeding into
>>>> the platform. All the signals then came back on displaying red before
>>>> normal operations resumed.  Anyone know what happened.

>>> Sounds like a power surge or a brief power failure. With a power surge,
>>> all of the circuit breakers have to reset, then all track circuits
>>> "drop" causing signals to go to normal (stop). The signaller then needs
>>> to run the time releases to put them back to proceed (usually 1 to 2
>>> mins)

>> Strangely enough, this happens on a very regular basis, at least once a
>> week.

> All the signals going "dark" is a pretty strange occurrence as signals
> actually run off battery power.

Only in the country.

> The batteries are kept in a constant state of charge by mains power but
> if the power were to to go out the batteries should be able to keep
> everything running for at least 5 hours, usually much longer.

In the Metro area, all the signalling runs off the AC Signal Power Supply.
This is 'traditionally' a 2.2kv feed from each traction sub, each section is
normally fed from each end so if a sub falls over that section can be fed
from the other end. There are variations, 2 recent installations use 1kv
(mining?) gear (Cranbourne & Upfield lines).  A slightly earlier
(perticularly nasty) job was the Epping line, which has 2 Mains feeds into
each location (from each side of the line iirc), this is fine until the
Mains supply is subject to a major failure, then you have nothing.

> point motors, boom gates, signals all can run off batteries for
> extended periods of time.

Point motors are almost always AC in the metro area.  Flashing Lights always
have a battery for the lights and bell, the booms can be either AC or DC.
AFAIK DC is the current standard.

> A train shunting a track circuit however will drain batteries relatively
> quickly compared to the same track circuit being unoccupied.

The tracks at Camberwell will be plain 25Hz AC tracks.  AFAIK even the High
Voltage and Jointless tracks run straight off 24v rectifiers off the AC sigs
supply.  You can't use DC tracks in DC traction territory, otherwise the
return current would have this habit of picking the tracks under the train.
:-/

> Sounds like Camberwell has some serious signal problems if its signals
> are going dark.

Sounds like Camberwell has a fubar AC supply.

> Mark
> Union Pacific Signal Maintainer

B.
Nothing in Particular.