Why build a boring old bullet train when you could create something that has the potential to change mass transit forever?

That's the question being posed by Tesla Motors and SpaceX founder Elon Musk, who on Monday unveiled the first conceptual designs for the Hyperloop, a theoretical rail system he's proposed as a better, cheaper alternative to the high-speed train California has been considering for some time now.

"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 document detailing his idea.

The Hyperloop would consist of aluminum pods suspended on a thin layer of air inside two steel tubes, one running in each direction. Using magnets on the pods and at various points along the track, the Hyperloop would propel the pods at speeds of up to nearly 800 miles-per-hour, with solar panels on top of the tubes serving as the primary power source. At that rate, passengers could make the 380-mile journey from Los Angeles to San Francisco in just over half an hour.

While high-speed trains already in use can hit speeds of around 300 mph, the Hyperloop would best that by using vacuum pumps to artificially maintain a low pressure environment inside the tubes. Though the tubes would not be completely vacuum sealed — the cost of maintaining a "hard vacuum" would be enormous — they would be kept at a pressure equal to one-sixth of that found on the surface of Mars, thus reducing drag 1,000 times relative to what's normally found at sea level.

Think a much faster, much larger version of those old pneumatic tubes used to ferry canisters of cash around banks.

Musk estimates it would cost around $6 billion to get the Hyperloop up and running. Still, that's significantly less than the $70 billion projected price tag for California's proposed high-speed train system.

It was that inefficiency which led Musk to design the Hyperloop in the first place, a point he reiterated Monday.

"How could it be that the home of Silicon Valley and JPL [NASA's Jet Propulsion Laboratory] — doing incredible things like indexing all the world’s knowledge and putting rovers on Mars — would build a bullet train that is both one of the most expensive per mile and one of the slowest in the world?" he wrote.

For now, the Hyperloop is still just a dream. Musk has no plans to develop it commercially, saying he's still focused on his existing businesses.

Until someone does develop the Hyperloop, we'll all just have to settle for high-speed trains or, in smaller towns, the good old monorail.