I’m assuming this question was promoted by the rather excellent video below?! I must confess, since watching it, I’ve been having similar thoughts myself!
I don't think I've seen that video before - I'll check it out thanks!
Actually it was prompted by my reading on Christian Wolmars History of BR book, which is a bit of a potted history and has a few pages about APT. It's a train I've always been intrigued by and wish I'd had a ride when it was operating (even though I'd have been a very small boy). My dad (not a rail enthusiast) rode it a couple of times by chance but can't recall much
There are three machines I wish I'd ridden/seen when I had the chance:
Concorde
The Vulcan
APT
Given the changes in technology and the likely obsolescence of the original specification, not to mention the fact it was only ever a prototype and so there's no handy source of spares, any attempt to restore it to mainline condition would result in nothing more than a hollow shell with a modern unit inside. It'd be about as convincing as LSL's Blue Pullman HST, and less original than the 5BEL trust's proposals. Yes, all heritage engines are like this to some degree, but the point is: do people want to preserve it for engineering reasons or 'look and feel'?
Well all the unique parts built specifically for APT could presumably be remanufactured at the same sort of cost as the originals (allowing for inflation of course). The motors are just motors. 1980's electronics might be more difficult of course but grafting a modern traction package onto 1980's trains has been done before (321 etc).
The entire APT project spend was less than £30m in 1980's money and that included a lot of fundamental research into vehicle dynamics.
I'm not pretending it would be cheap, indeed it would be very expensive. But if someone with the money came along would it be feasible is the question I'm asking? It does look so modern, even 40 years later.