It's definitely linked to the signalling at Woking. On Platform 3 (the up bay) it will play either 30 seconds before departure if you have a proceed aspect, or immediately before you get a proceed aspect otherwise.
On the topic of this, a train being in a platform will be recognised by a headcode being in a particular train describer berth and therefore the announcement will play as long as the train is present in this particular berth. Obviously you'll always be in this berth if you are in the platform, even with the signal at red at the end.
However the difference with a bay platform is there are generally two berths (sometimes more), and the information system generally only looks at the departure berth (the one you jump from when you pass the signal), and the headcode will generally only go to the departure berth when the signal clears - headcodes are generally setup at the buffers.
This is a new thing I have only recently seen, Brookwood has been doing it for about a month or two. Woking doesn't appear to do this, but Guildford does.
Why of all stations they chose Brookwood, when it has no dwell time unlike Woking or Farnborough I'll never know.
This is the whole point, the 2nd and 3rd trains won't be going anywhere until the 1st one has gone, so I don't see how it's unhelpful at all. Southern have been doing this for years at their stations. It's a new thing to SWT from what I've seen recently.
It has been used by SWT for years too, however SWT seem to adopt it for particular trains, and don't go for the slapdash Southern all stations all trains approach.
"Platform X for the hh:mm GWR service to Destination, which is ready to leave." seems to be a London Paddington favourite
Heard it once or twice at Cardiff too.
That's used all over the country, Kings Cross, Euston and Paddington all have it automatically setup to play for trains, anywhere else with any ATOS announcers can play it at the click of a mouse!
