What Musk has said so far is that the Hyperloop would be a "a cross between a Concorde, a rail gun, and an air hockey table," and would be able to deliver people the 380 miles between Los Angeles and San Francisco in just 30 minutes, dramatically outpacing California's bullet train project, which would make the same trip in just under three hours. Musk has publicly bashed California's bullet train plans as inefficient, and maintains that the Hyperloop would be a better project for the state to undertake. He first brought up the idea for the Hyperloop just about a year ago at a PandoDaily fireside chat and said that he would provide further details on June 20th this year, but it looks as though we'll all have to wait until August to learn more about how his proposed system would function.