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Waterloo co-acting signal query

Unread postPosted: Wed Apr 19, 2017 7:10 pm
by colin1501
As part of the preparatory works for the lengthening of platforms 1-4 at Waterloo, a new gantry has been erected across the ends of platforms 1-8. On platform 8, this gantry carries a new signal - already in use - about a coach length in from the platform end (ie, towards the concourse), so that the front of a 10-coach (444) or 12-coach (450) train is beyond it. This signal is numbered W15. At the very end of the platform, the original 'starting' signal is still in use, now numbered W15CA. I understand the CA suffix to indicate 'co-actor', but if this is the case aren't these signals the wrong way round? Shouldn't the 'main' signal be right at the end of the platform, with the co-actor further back, perhaps for easier sighting from shorter trains?

Colin

Re: Waterloo co-acting signal query

Unread postPosted: Wed Apr 19, 2017 7:16 pm
by Chris Osment
Ought not co-acting signals to be at the same point relative to the track anyway, rather than one in rear/advance of the other?

Re: Waterloo co-acting signal query

Unread postPosted: Wed Apr 19, 2017 8:15 pm
by steve thompson
How do the TC's work then? if the front of a train was past W15 the signal should be at red ?

Re: Waterloo co-acting signal query

Unread postPosted: Fri Apr 21, 2017 9:39 am
by scarpa
Its quite likely the track circuit in advance of W15 CA is the replacement track for both signals.

Re: Waterloo co-acting signal query

Unread postPosted: Sat Apr 22, 2017 8:38 pm
by Signal-sighter
Chris Osment wrote:Ought not co-acting signals to be at the same point relative to the track anyway, rather than one in rear/advance of the other?

No, the Standards currently permit up to 20m difference either way longitudinally and any position laterally so long as the Signal Sighting Committee can justify the reasons why.