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Waterloo co-acting signal query

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Waterloo co-acting signal query

Unread postby colin1501 » Wed Apr 19, 2017 7:10 pm

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?

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Re: Waterloo co-acting signal query

Unread postby Chris Osment » Wed Apr 19, 2017 7:16 pm

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?
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Re: Waterloo co-acting signal query

Unread postby steve thompson » Wed Apr 19, 2017 8:15 pm

How do the TC's work then? if the front of a train was past W15 the signal should be at red ?
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Re: Waterloo co-acting signal query

Unread postby scarpa » Fri Apr 21, 2017 9:39 am

Its quite likely the track circuit in advance of W15 CA is the replacement track for both signals.
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Re: Waterloo co-acting signal query

Unread postby Signal-sighter » Sat Apr 22, 2017 8:38 pm

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.
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Re: Waterloo co-acting signal query

Unread postby scarpa » Mon May 22, 2017 7:42 pm

A visit to Waterloo platform 8 revealed what might be going on with signal W15. A new gantry has been erected across platforms 1 to 7 with an additional small section cantilevered from the right side upright with the W15 3 aspect head and RI. As platforms 1 to7 are extended the platform signals will be added to the gantry. At present a 442 type of train, two units coupled together stands nearly two coaches past W15 signal. The original structure which has W15 CA fixed to it has a left side long cantilever with platform signals 6 and 7 fixed on it. It's an old signal cantilever and may well be in the way for remodelling. There was no alteration to the track circuits. The existing replacement track replaces W 15 CA and W 15 to Red when the train occupies the track circuit. The signal plates are correct. A train approaching a signal at red, the driver would expect to see the signal with an I.D. plate not with CA [co-actor] on it in the first instance. As platform 8 will be reduced in length if W15 CA is removed, it may be planned to renew the signal.
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