Re: Bayside Trains driver stood down.

[Wallabz <wallaby@fl.net.au>]

Hiyas :-)

Exnarc wrote:
> Mark is right,even in NSW the operation of crossings is the same as
> Victoria.
> 
> The operation of level crossings is acheived by the train entering a track
> circiut section governing that crossing.

Close, but there are some significant differences.  I'm talking about
NSW, because that's where I'm qualified as a signal electrician.  I
don't know much about Vic other than that there are some differences.
 

> In the case of a location where the crossing is also protected by a fixed
> signal, (be it a Home or an Automatic), the crossing track circuit is also
> tied in with the signalling circuit.

NOT if the signal is an auto.  The crossing is only "protected" by the
fixed signal if the fixed signal is a controlled signal.  A level
crossing in an automatic area is never deemed to be *protected* by an
automatic signal, whether that signal is adjacent to the crossing or
otherwise.  Otherwise, the *signal* and the *level crossing* are
independant of each other.  This is not to say that common signalling
equipment (ie. track circuits) does not govern the operation of each,
just that an *auto* signal doesn't care about the state of the
crossing.  There are exceptions, but in NSW, *most* of the time, esp on
main lines, this is the case.
 

> i.e: If the signal is at proceed the crossing will activate as soon as the
> train enters the crossing circuit, (usually about 500 or 600m before the
> crossing, this can vary with track speed and crossing predictors but its OK
> for this explanation). If the signal protecting the crossing is at Stop the
> circuit will not activate, the booms etc. will not work.

True enough in a controlled area, where a crossing is protected by a
home signal.
 

> However if a train over ran this signal or if the Driver was operating under
> Rule 1, Section 3 (Reg 74 for you Mark), as soon as the wheels crossed the
> Bell Block for the signal the Booms would activate and the lights start
> flashing.

Yes.  This is the case in NSW.
 
As to another post in this thread which indicated that in Vic, the
signal protecting a crossing could clear when an express is approaching
*before* the booms are at zero degrees, this is an absolute no-no in
NSW.  If a signal is interlocked with a level crossing, usually the
*only* detection the signal relies on is zero degrees position on both
booms and the XR(Crossing Control Relay) down. 

I have a lovely circuit of a simple single line auto xing for any
technophiles out there, it's a clever piece of work, allowing the
departure track to be not detected to the crossing can stop operating as
soon as the crossing track is clear, depending on the approach direction
of the train.  If anyone wants it I'll scan and www it. :-)

Cheers
Shaun