Efficiency comparisons
The obvious efficiency comparison is with non-maglev high-speed rail and that shows at best a marginal benefit at higher speeds, which is academic here in the UK as we don't have anything remotely resembling high-speed trains.
A more useful comparison is with short-haul air travel, which is horrendously innefficient in terms of greenhouse gas emissions per passenger-km. The reason passengers like myself prefer air over rail on short-haul routes is journey time. I'd rather fly from Edinburgh to London thatn take the train: over a distance of ~800km the train gets me from town centre to town centre in 6 hours by train while the plane trip takes about 3 hours including checkin and time to get to and from airports. I'll happily take the train if it gets me from a central station to a central station in under 3 hours. More legroom, better bar, no mobile phone bans, no checkin queues, better toilets etc.
Trains are vastly more environment friendly than planes so moving those short-haul journeys from air to maglev could bring serious environmental benefits, not least reducing the rampant growth of airports.
Biting the hand that feeds IT
