In message , martyn dawe
writes

I know computers of that vintage would have had air-con, so have LUL
not maintained the Air-con in all that time ?

If you're referring to the fans seen in a recent BBC clip, I don't think
they're used for cooling anything as advanced as a computer. It looked
to me like they're for cooling the thermionic valves that are still used
in the signal relays. (I did wonder where TfL manage to source
replacement valves these days!)
--
Paul Terry