Re: Three Position Signalling

[cmgord@ecr.mu.oz.au (Christopher_Martin GORDON)]

: > Also on loops on the BG.
: >
: > The only way to get the signal off for a movement into no.1 road and not
: > have the departure signal off is to reverse the points at the far end.
: > The after the arrival signal is off then the points at the far end are still
: > free to move (ie you can move them back).

: Are you sure? AFAIK once you set up this move the points at the far end are locked until
: you either put the home arrival back to stop or the train passes the home arrival at low
: speed caution and enters the "yard" area either main or loop.

Will I think that is true for the standard gauge, but what about the BG loops
around.  One I can think of is Herns Oak (Between Moe and Morwell).  It is
controlled from a panel at Morwell and when I was there late one night the
signaller showed me how to get the main line signal for No.1 road off.  The
first way was reversing the far end points, then the signal would come off,
the points still had the "free to move" light and he restored them to normal
(ie moved the far end points).  I would of thought that these points would be
locked, but they wern't that is why I got him to restore the points while
the signal was off.


: I think you'll find some interlocking here preventing that. This interlocking is probably
: in the Office equipment and thus field circuits do not show it but that is how I
: understand it would work. It always did when I worked on the system.

Same again, down at Herns Oak.  Once the departure signal for No.1 road was
off the arrival signal was off, he put back the departure signal and the
arrival staied off.  After a little while he then had avaibility on the 
points (the ones locked by the departure signal)./


So on the SG what happens when say the up train is signalled into no.1 road
(ie arrival is off) and the down train is signalled into no.2 road.  The
down arrives can you then restore the points and let the up train have a 
clear run through the loop?  Or do you have to wait until the up train 
enters the loop (or you put back the arrival signal).


--

Chris Gordon
http://www.ecr.mu.oz.au/~cmgord

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