It's always interesting seeing lighting on transport, the class 507 & 508 merseyrail trains here in Liverpool were all delivered in the late 1970s with Thorn warm white 4ft 40w tubes throughout and the lampholders looked like the Thorn Atlantic lampholders although they were covered by half round plastic to stop people removing them. They were refurbished in 2005 and the lights are now behind opal panels.

interesting I remember boarding the tube once and seeing IIRC PowerTwist T12s... one of my Other hobbies is London Transport Buses hence why i was at the bus rally another interesting thing is in the 1990s all but 3 or so of the RML Bus fleet where refurbished (fitted with new engines and lighting) and the saloon lighting was replaced by fluorescent tubes, I always thought they used regular T8 tubes, it was during a restoration of an RML that i saw the "fixtures" used US slimline tubes much to my surprise, I wonder how Bus owners these days acquire replacement tubes... (granted the proper thing to do is to re fit the proper tungsten lighting )

Used to like checking out those good old T12 5ft tubes in those bespoke fittings on the London tube!