My comment on the other thread:

"Here's the complete proposal: http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201.... It's absolutely incredible. Low pressure tube that overcomes air pressure in a tube by having lateral fans push the small amount of air through the capsules, while the capsules is elevated on a small cushion of air produced by the capsule itself, essentially like an air hockey table, but the puck is providing the air. With electric motors like the ones in the Tesla Model S, as well as solar panels on the top of the tube, it would be completely capable of providing all the energy needed to power it. The tube would be built on pylons following I-5 (essentially a straight line) from SF to LA and be capable of covering the distance in half and hour. Since the tube is on pylons, there is little cost in buying land, drastically reducing cost. The entire proposal would cost $6 billion dollars, compared to the current proposed "bullet" train that would cost 68 billion. A one-way ticket would cost around $20. Since the tube is extremely simple, upkeep would be extremely minimal, and the chance of failure in the tube or capsule is very small. Absolutely astounding."