Re: Signalling in Victoria

[Notagunzel <notagunzel@bigfoot.com>]

Christopher_Martin GORDON wrote:
> 
> Could someone help with signalling please.
> The signalling on the Racecourse Line (melb) is Automatic 2
> position signalling, am I correct in saying is the signal is Green
> the it is proceed, Red is Stop.  With a 'A' plate on the signal it
> is an auto and can be passed at stop (etc..) Without the 'A' it is
> a Home signal? Where there is two signals one next to the other
> they give proceed to either the left line or the right.

Looks OK to me...
 
> Other two position signalling, what is the first signal from auto
> block signalling called? Home? then you get to the first station and
> the usual distant, home, (station), starting.  Now the distant will
> only change from yellow to green when;
> a) the home signal is set to proceed
> b) the starting signal is set to proceed.
> Is there any locking of the starting signal (ie with trains in the
> section)?

Usually a Home, and the last auto doen't display a Green aspect untill
ALL the 2 pos. signals are off, mush the same as a 2 pos. Distant. 
Distants are released when all the Homes are off, but theres always
exceptions - the Down Distant at Wodonga applies only as far as the Down
Departure.(!)  Starting Signals may be Track Circuited sometimes, but
are never released by Double Line Block Instruments.  There is only one
place where I know of them being released by the Electric Staff
(Newport), and if the next section is Track Block (Nth Geelong A - B -
Geelong A only) then the entire section is track circuited, and then
controls the Starting Signal.
 
> What is the last signal from two position signalling to auto block
> signalling? repeating?  What are the indications, i think
> yellow over yellow,  next signal at stop.
> green over yellow, next signal at proceed
> and the light are swaped over to show medium speed? is there any
> where now that shows medium speed on a repeating signal?

3 position repeater signals are actually just a '3 position' distant,
and can display:
Yellow/Yellow - Next Signal at Stop,
Green/Yellow - Next Signal at Proceed (displaying a normal speed aspect)
Yellow/Green - Reduce to Medium Speed.

There are Repeaters showing Y/G at Seymour & Ballarat, probably other
places too.
 
Repeaters are used to repeat Points in a few places as well.

> Calling on signals are just like low speed caution? ie line may not be
> clear.

Basically.. Calling On signals are always under a Home, and when the
Calling On is off, it means the driver can proceed along the route
governed by the home being prepared to stop short of any obstruction
etc...
 
> Disc signals and dwalf signals? Do disc signals show red and green, and
> are they indicating the track is clear or not? and dwalf show red and
> yellow, or red yellow or green.  Yellow is line may not be clear, green
> is line clear.  Are they any dwalf signals that show green in use in
> Melbourne?

Disc signals govern moves in and out of sidings, also 'wrong line'ish
moves.  When off, the driver must be prepared to stop short of any
obstruction.

Dwarf Aspects:
Red - Stop
Yellow - Low Speed Caution
Green - Clear Low Speed.

For a Dwarf to show Green, the Track must be clear to the next signal,
and the next signal must be off.  There are quite a few, Burnley,
Bayswater, Nth Geelong C, Maryborough...
 
> One last thing, the centre line on the Box Hill line is Track control
> and the city loop and centre line on the Frankston line are auto block
> signalling why the difference? what is the difference?

As far as the drivers are concerned, its just rules.  ATC has a special
caution order to enter the section, ABS doen't (I think thats it). 
AFAIK single Line ABS is only found when the same signaller controls
both ends of the section, but there are places where the signaller
controls both ends of a ATC section.

Centre line to Box Hill is Automatic And Track Control, it used to be
Lever Locking and Track Control, LLTC was rolled into ATC when the 1994
rules appeared.  There is actually a control lever at each end of the
section, so that Box Hill must reverse its lever before Camberwell can
pull the Home Departure off.  The Signals actually hang of a '4 wire'
system, so if both Departures at each end are at stop, then all the
intermediate autos are at Stop.  When one of the Departures is pulled
off, the autos will clear away the Departure being pulled off.  After
the train passes an auto, the auto will remain at stop unless the
Departure is pulled of for the next train.

The Underground Loop was originally LLTC (same as the Bidirectional
Running across the Viaduct), and there are control levers at each end of
the section.  When there were still individual boxes, they had to be
worked as normal, but AFAIK the route setting logic at Metrol does it
automatically now.

As for Caulfield - Moorabbin, AFAIK it doen't have Control Levers, but I
don't know if it's a '4 wire' or a '2 wire' system.  2 wire systems are
like the NE SG CTC, (and the Western CTC) where the intermediate autos
reclear after the passage of a train even when the Departure in the Rear
remains at Stop.

After ploughing thru that, I hope it helps..

BC