Beach Pneumatic TransitElon musk, head of both Tesla Motors and SpaceX, has been talking about a mysterious new mode of transportation he’d like to see that he calls the Hyperloop. He has referred to it as a “cross between a Concorde and a railgun and an air hockey table.”

He’s keeping details close to the vest, but, Jay Yarow at businessinsider.com has dug up a very plausible explanation for what Musk might have in mind.

Back in 1972 R. M. Salter at the RAND Corporation produced a paper describing what he called a Very High Speed Transit. This would be a hypersonic (Mach 5+) train running on magnetic levitation in a vacuum tunnel. Frictionless transportation could whisk passengers from New York to LA in 21 minutes. Reminds me of the Beach Pneumatic Transit built by Scientific American editor Alfred Ely Beach in New York City back in 1870.

Musk isn’t talking about that kind of speed, but he does say that he envisions the hyperloop making the trip from LA to San Francisco in 30 minutes. That works out to an average speed of about the speed of sound (same as the Concorde airliner).

In a May 15 Twitter post, however, Musk dismissed the vacuum tunnel concept.

Will publish something on the Hyperloop in about four weeks. Will forgo patents on the idea and just open source it. Not a vac tunnel btw.

In a CNBC interview, Musk says he might give more details on the Hyperloop after a planned announcement from Telsa on June 20. He also says he doesn’t see building it himself, but that he hopes someone else will take it up (the Hyperloop discussion starts at 6 minutes, 55 seconds into the interview).

Anyone else care to speculate?