Speed and energy usage. The idea as I understood it was to compete with commuter flights; if i understand your idea correctly you are proposing a slow, lightweight trolley on elevated rails?
That was the hypothetical to break down where the cost savings come from. It would not be as fast, no, but you might be able to get up to high speed train speed's with it.
Energy savings are mostly moot if you power things from overhead wire/ third rail. Electricity is cheap(I'm actually curious why this isn't part of the proposal).
So it's benefit is speed. It's a very big benefit, but the tolerances for the air baring/tunnel wall it rides on are really really small.
Grid power is in the proposal as a backup source for cloudy days. I think the main point of covering it with solar aside from his stake in the solar sector was to show that you could do so and still come out cheaper than the high-speed rail proposal.
I agree about the air bearing tolerances seeming like a big problem.
Energy savings are mostly moot if you power things from overhead wire/ third rail. Electricity is cheap(I'm actually curious why this isn't part of the proposal).
So it's benefit is speed. It's a very big benefit, but the tolerances for the air baring/tunnel wall it rides on are really really small.