Re: [Melb] Broadmeadows re-signalling

["Exnarc" <gwrly@netspace.net.au>]

John Duncan McCallum <mccallum@melbpc.org.au> wrote in message
3802FDC9.F53BF1E4@melbpc.org.au">news:3802FDC9.F53BF1E4@melbpc.org.au...
>
>
> Exnarc wrote:
>
> > The reason for Somertons mixture of 2 and 3 position signalling would be
the
> > result of the Standard Gauge being opened in 1962, whilst the station
layout
> > is fundermentally a 2 position area, the fact that it has access to
cross
> > the SG Mainline would have necessitated the use of 3 position signals,
note
> > that only those BG signals that protect the grade crossing are 3
position.
>
>
> > Bob.
>
> That is not quite true, as the only 2 position signals at Somerton are
> as Chris
> stated, namely, the two starting signals and the down home ex Upfield.
> All others
> are 3 position.
> At Kilmore East, the BG signals protecting the Apex siding are 2
> position.

John & David,

 I used the example as an explanation for the use of three position signals
not that it was a requirement for them to be 3 position, actually if memory
serves me right, the BG down arrival is 3 position, which protects the grade
crossing, preceeded by a Repeating Signal, (I won't enter into the debate as
to whether  they are 2 or 3 Position), on the down line beyond the Home
signal is a 2 position Starter (with an illuminated letter A), On the Up
there is a Repeater (indicating that you are going from a 2 Position to a 3
Position Area) followed by a 3 Position Home, then a 3 position Home
protecting the junction (BG track to the grade crossing), followed by a 2
position Starter, the only 3 Position signal that doesn't protect the grade
crossing is the Up Arrival Home which I would assume was made a 3 position
signal to protect a train standing at the Inner Home (if the Arrival Home
Signal was not 3 Position the Repeater would have to have been a Distant
signal) , the Inner Home is a 3 Position Home purely to compliment the Down
Arrival Home. if this wasn't the case there would be no need for 3 Position
Signalling at Somerton at all!!!!

As for the statement that Somerton is track circiuted, yes it is, except for
the Upfield Line which was Electric Staff, the Down Arrival (2 Position)
Home from the Upfield line however, (Iam not 100% sure) is not track
circiuted far as the 3 Position Dwarf that protects the entrance to the
yard, (hence the need for the Arm to be fixed and the need for the Calling
On), I would assume other than for the protection of the points that the
Dwarf wasn't track circiuted either?

The Kilmore East example was a much later addition,and I would assume was
done as a cost saving exercise, the grade crossings at Broadmeadows,
Seymour, Benalla, Wangaratta, Bowser were also protected by 2 Position
signals all (with the exception of Seymour) were little used (1 or 2
movements a day at the most).

In the case of Somerton it was necessary to carry out major works due to the
need of the SG to have access to the yard, this being the case, it was
probably easier and cheaper to provide circiutry for 3 position signals than
to mix 2 position with 3 position when it came to the CTC.

I'm only trying to explain why Somerton BG junction is 3 position, but if
you think about it, it sounds reasonable!!! (Anyway it's worth considering).

Bob.