I was thinking more of the Pumping House for the Atmospheric Railway built by Brunel - which was a clue https://www.nationaltransporttrust....-detail/starcross-atmospheric-pumping-station
Nope - the route has had third rail for a very long time and still has today. - unit number is a clue
The WB on the signal is the old Southern Railway designation They went down a route with a fixed letter and the next box on the route incremented by one letter.
The 508s started life on the Southern in 1979 https://www.flickr.com/photos/86020500@N06/7982098614 But from 1983 were reduced to 3 cars and sent north to Merseyrail with the 4th TSO going in to the 455/7 https://sremg.org.uk/emu/class508.shtml
Correct - the route I was using is off Wotawallys site https://www.wotawallysbits.co.uk/trevor-wood-routes 1960's Waterloo Suburban Lines v1.0 Your turn
Now you say it, I can't unsee it being Vauxhall and I feel like an idiot for not immediately recognising it. I didn't even see the other platforms!
Well it is two Scotrail 158s on an Electrified Route near a river so I can think of Suburban Glasgow but I don't have the route