Maglev trains are worryingly attractive to bigheaded politicians who want to talk high tech. The one at shanghai only gets up to half maximum speed before having to slow down again – but it looks great in the ‘Come to Shanghai’ literature.
Maglevs need about a minimum 80 mile run to be worth having, when most aiports are about 30 miles from city centres. They are too expensive for ordinary cross country routes, although travel at 360 mph would be good for going from London through the Channel Tunnel one day.
Where they might be useful now is for airports which are 80-100 miles from London (or equivalent capital cities). London airport could move out to Salisbury Plain and Heathrow could be given over to residential use. I think we need John Redwood to work on it!