Tech visionary Elon Musk, known for his SpaceX and Tesla Motors ventures, has unveiled a concept for solar-powered ground transportation at nearly the speed of sound.

Dubbed Hyperloop, the "extremely speculative" plan envisions pods traveling on a cushion of pressurized air through low-pressure tubes at speeds of around 1,220 kph (600 mph).

"Short of figuring out real teleportation, which would of course be awesome (someone please do this), the only option for super fast travel is to build a tube over or under the ground that contains a special environment," Musk wrote in a 57-page proposal.

He estimates a functioning hyperloop between San Francisco and Los Angeles would require an investment of around $6 billion and that the project would be economically viable at a cost per ticket of about $20.

Hyperloop capsules could cover the 550 kilometers (342 miles) between the two California cities in 30 minutes or so, Musk said.

A $68 billion high-speed rail service linking Los Angeles and San Francisco is scheduled to become operational in 2028.

The hyperloop initiative could be implemented with existing technology, Musk said. EFE