Re: Crossing loop design (r.e. Southern Aurora crash)

[Notagunzel <notagunzel@bigfoot.com>]

Christopher_Martin GORDON wrote:
> 
> : > 0 or 1, Clifton Hill group
> : > 2 or 3, Burnley Group
> : > 4 or 5, North Melbourne Group
> : > 6 or 7, Caufield Gorup
> : > 8 or 9, Special (incuding Sandringham)
> 
> : Newport and Sunshine used 6/7
> :
> : Up end of Nth Melbourne has the intuitive prefix IAA (Inner Area A?)
> :
> 
> I picked this up when looking at a photo of Newport Signals.
> I looked at some diagrams and it looks like 6/7 is used for the Through
> Surburan from FSS to NME and then for the lines through Sth Keng, (to
> Footscray) and the lines over the top to Broadmedows as far as Keng.

I think in the original Metrol Areas, 1 = CHL Area Controller, 3 = BLY
Area Controller, 5 = NTH Area Controller, 7 = CFD Area Controller, 9 =
SHM Area Controller.  They had a wizzo idea that a train would remain
under one controller, instead of a controller for FSS, and one for SSS
etc...
Anyway, the Down end of Nth Melb never went to these controllers, a new
Western Controller was created for Nth Melb JCT & SKN.  They also have a
Clifton Hill Area Controller, for Clifton Hill, and somewhere along the
line the SHM Areas was rolled into the CFD Area.

> How do they number the signals?
> At Burnley going toward town on parrell tracks:
> From Box Hill: 379, 377, 277, 273, 375, H108, H100, 373, 371
> From Glen Wav: 281, 397, 297, 293, 395, L108, L100, L98, 391
> 
> so apart from the first signal they are 20 different, but the numbering
> is wrong, what happened to 275 and 295? other wise it is logical.

Newport appears to have been layed out by a bloke from NSW, as the Point
No.s are all in a row, instead of being 100 less than a signal applying
over them, as is all other 'Metrol' style applications.  The Signal
Numbering is less elegent also.

BLY 281 is an uncontrolled auto immediantly in advance of BLY381 (logic
continues) whereas BLY379 is a home.  Having Sig Numbers 10/20 different
on parralel lines is present thruout 'Metrol' style places.

373 is a home, used to be a controlled auto, whereas L98 is an auto. 
This is to do with the fact you can't reverse a 3 pos signal with a
trailing turnout foul in the overlap, whereas you can swing the overlap
on facing points in the overlap, providing the second track is clear,
otherwise the LR (Lock Relay) for the points stays down.  Unless the
second track is a siding, witness the admission of the Willy shuttle
into the Altona Car Sidings at Newport.  Train arrives into plat with
pts set for Melb.  After x seconds (Route Locking picks up) points motor
reverse, and a Low Speed for the train to enter the siding.

BC