SpaceX announces design competition for Hyperloop

Suggested by Musk two years ago, the idea is to zoom passenger capsules through elevated tubes between Los Angeles and San Francisco at speeds of up to 750 mph. The concept pulls together several proven technologies: Capsules would float on a thin cushion of air and draw on magnetic attraction and solar power to zoom through a nearly airless tube. With little wind resistance, the capsules could reach the speed of sound and the 400-mile ride would take a half-hour.