It sounds intriguing. I wonder what his idea is. My thought is that is a kind of train in a mostly vacuum sealed tube to eliminate friction and maintain stability. That's the only way I see they'd be able to maintain the 900 mph speeds they want to attain safely. You'd think that something like this would be tried first on the east coast though, where the ground is much more stable. California just seems too unstable to develop such a system having multiple major fault lines running through it.