Apparently British Rail did file a patent for a flying saucer and there are several videos on YouTube about this subject. I'm not too sure if they thought that the railways would be obsolete when the Starship entered service but the original purpose was a heavy lifting crane which kept getting bits added on the design.
It was supposed to be powered by a nuclear reactor, the Americans and the Russians were interested in fitting a nuclear reactor in aircraft. The Russians actually did this but the crew suffered from radiation sickness.
Well if they work in submarines then a Starship shouldn't be a problem, of course health and safety would be a major hurdle to overcome but if British Rail managed to overcome all the technical difficulties, I wonder what it would have looked like?
Would the passenger seats revolve like the restaurant at the Post Office Tower or look like something from Star Trek? Or something Thunderbirds had a go at?
Maybe Kit would know?