Re: Signalling in Victoria

[Gavin Potter <gavpot@ozemail.com.au>]

Christopher_Martin GORDON wrote:

> Ok, just a couple more questions about 2 position signalling.  The numbers on
> the signal posts are usually the lever number, and where there are many levers
> the first lever number is on the post.  Is this correct?  If so then in places
> like Sunbury the lever (switch) number has no relationship with the post
> number.

No: Signal numbers 99.9% of the time do not correspond with lever numbers. In a
signal box there are levers for points, looking bars and signals. To put a single
signal to proceed could require more than the three levers to be reversed.

>
>
> Disc and dawf signals. Most sidings and wrong line moves have/had disc
> signals, if you have a colour light signal is it called a disc, or a two
> position dawf?

Coloured light only (search light signal) were dwafs.

>
>
> Eltham has two homes (on for each road) and a dawf/disc for the sidings, this
> is a little like the Showgrounds (ie it has a 'siding' sign and it normally
> off, but shows yellow for moves into the sidings), I spose in the days of
> semaphore signals this would have been a disc.

Correct

>
>
> Now three position signalling.  Where you have a signal that shows red/red,
> yellow/red & green/red it is three aspect signalling?

Don't get confused. It is 3 position signaling. The number of different aspect
that can be shown by the signal has nothing to do with the type of signaling
system that you are running under.
A signal in a 3 position area can show up to 8 aspects if it has been configured
to show all aspects, or it could only show one aspect.
The aspects that  could be shown are:

R/R=stop
Y/R=normal speed warning, next signal is at the stop position.
G/R=clear normal speed, the next signal is at the proceed position and will be
showing a normal speed aspect.
R/Y=medium speed warning, the next signal is at the stop position.
R/G=clear medium speed, the next signal is at the proceed position.
Y/G=reduce to medium speed, the next signal is at the proceed position, but the
speed of the train must be reduced to medium speed by the next signal.
R/R/Y=low speed warning
R/R/Y=clear low speed.

>
>
> Where you have red/red, red/yellow, yellow/green & green/red it is four aspect
> signalling?

No, see above.

>
>
> Where you have say a junction and the signal shows red/red, yellow/red &
> green/red for one route or red/red, red/yellow & red/green apart from the
> being a home signal would you say the signal has 5 aspects?

No, see above.
Also, three position signaling is used as speed signaling, i.e. normal speed,
medium speed. At a junction, usually the diverging line will be signaled in the
medium speed aspect.

>
>
> Signals the clear in the following order: red/red, red/yellow, yellow/red,
> yellow/green, & green/red (I think that is right) it has the yellow/red aspect
> because a full overlap is provided after the train has past some point, but
> the next signal is still red/red.

No. You could get the following aspects from a signal after a train has passed it.

R/R, R/Y, R/G, or
R/R, R/Y, Y/G, G/R, or
R/R, Y/R, G/R

>
>
> All dawf signals are three position (in three position signalling area) but
> some only show two aspects.  The signals at either end of the centre road of
> Clifton Hill are three aspect with trip levers.  Are these dawfs, or home
> signals, or something else?

Dwaf signals are two position signals.
I cant remember if the centre road at Clifton Hill is a through road. They could
be home signals or dwafs. You would have to check the signaling diagram. It has
been a long time since I was driving down that way.

>
>
> Transition from Two position signalling to three position, sometimes it is
> like Greensbourgh where there is a home to post X and then post X is a three
> position signal.

Correct, and at other times you get a repeating signal as mentioned below.

>
>
> Or like St Albans where you have a home signal, repeating, then a three
> position home.  I think the repeating signal is like a distant (but with a
> yellow marker).  Is that right?

Correct, but a repeater is not a distant signal. It is a repeating signal. It
tells you the aspect of the next signal.
Y/Y= next signal at the stop position.
G/Y= next signal at the proceed position

>
>
> What colour are the arms on a semaphore repeating signal?  I know of only one
> semaphore repeating that was at Maldon Junction any I have no idea what colour
> the arms were.  The top arm was fixed at yellow, and the bottom yellow or
> green.

Repeating signals were lights only, well they were between 77 and 88 while I was a
driver.

>
>
> Well that's all I need to know for now (until I am totally confused again)
>
> Regards,
>
> --
> Chris Gordon
> http://www.ecr.mu.oz.au/~cmgord

--------------------------------------------------------
Gavin Potter.
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