[ricardobeat]

But it being very light is a consequence of the design as a whole. Light rail is already as light as it can be given cost/materials.

We already have rail transport on pylons, usually an implementation of a monorail[1], but it only solves the right-of-way issue. Everything else (energy consumption, speed, efficiency, passenger flow, safety) is not much different from standard transportation.

[1] http://en.wikipedia.org/wiki/Monorail

[anologwintermut]

I disagree about the weight. If you took the proposed capsule, added wheels, replaced the 1,500kg batteries with a motor and powered the thing from a third rail, you'd get something rather light with enough power to move at i'd guess 200 or 300 mph(think what you could get out of a Tesla if it had extra motors instead of batteries). This and the route would get you most of the cost savings.

The speed is the huge benefit, but involves a technical challenge of rather unknown cost: how do you build a tube for hundreds of miles with a down smooth surface at the 5mm level.

[ricardobeat]

That's what high-speed rail is. Wheels can't get you to 300mph, so you need maglev. The added weight would mean massive pylons, huge energy consumption. There is nothing new about that. It's more expensive, slower and less secure. Can you imagine the result of the recent spanish crash if the rails were elevated?

There is no easy formula for magic fast, light, cheap rail transport. Sorry - there is, it's called the Hyperloop :) the greatest thing about it is that all of it's advantages come from it's well thought-out, integrated design, not any one technology we don't have today.

[anologwintermut]

High-speed rail trains hold way more than 20 people, so they weigh more. Plus in the US, high speed trains that run on "freight lines" (which include the Acela) have to be very heavy do to some idiotic crash worthiness requirments. https://www.ebbc.org/rail/fra.html