Billionaire entrepreneur Elon Musk has revealed more information on his top-secret Hyperloop -- a vehicle he says will take passengers from Los Angeles to San Francisco in a mere half hour.

The Tesla Motors co-founder called the fast train "a cross between a Concorde and a railgun and an air hockey table" at the D11 Conference earlier this year. The pneumatic tube train system will be "twice as fast as what an average aircraft can do."

And in a tweet yesterday, he promised to publish the alpha design by August 12 and asked for feedback from his followers.

Once constructed, the Hyperloop will leave as soon as passengers board as opposed to running on a strict schedule. The train will also be weather immune which might put a damper on some people who still enjoy the occasional snow day.

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Some are calling Musk's idea pure insanity, but others -- including physicist Brian Dodson of Gizmag --are willing to give the Hyperloop a chance after examining all of its' parts.

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Dodson ruled out two theories that the Hyperloop will use a vacuum tunnel or a launch loop that accelerates vehicles electromagnetically along a cable system. Instead, he believes Musk's proposal is actually "a pneumatic transport system that consists of a closed tube making loops between Los Angeles and San Francisco" according to Discovery News.

English please? Essentially, passengers will ride in capsules within the tube similar to pneumatic tubes at bank drive-throughs.

“Even if I’m sort of wrong about the economic assumptions behind the Hyperloop, it would still be a really fun ride,” Musk said at the conference.

The Hyperloop still faces many challenges and hopefully questions will be answered come August 12.