It may be called pneumatic, but there's nothing new about the technology. The pressurized tubes have been around since the 1800s to move stuff through factories and offices.
But can a high-tech version of it move people from city to city? Musk seems to think so.
Musk describes the Hyperloop as a "cross between the Concorde, a rail gun, and an air hockey table."
Musk has a knack for making unconventional ideas work. He's the guy behind the electric car maker Tesla, the private space transportation company SpaceX and the e-commerce company PayPal.
In a teleconference Monday, he unveiled his plans for the Hyperloop.
"Actually it would feel like being in an airplane," he said. "There would be an initial acceleration and once you're traveling at speed, you wouldn't really notice the speed at all."
Musk says the Hyperloop would be able to hit speeds up to 800 miles per hour, zipping passengers from sunny Los Angeles to foggy San Francisco in less than 30 minutes.
The system would feature a large, nearly air-free tube. Inside, capsules would be pulled down the line by magnetic attraction.
Capsules would float on a cushion of air they create - like an air hockey table in which the puck produces the air instead of the surface. To minimize friction from what air is in the tube, a powerful fan at the front of each capsule would suck air from the front to the rear.
Capsules could depart every 30 seconds, carrying 28 people, with a projected cost of about $20 each way, according to Musk's plan. The proposed route would follow the I-5.
California's high-speed rail project would take more than 2 1/2 hours from Los Angeles to San Francisco. Musk says the state needs to scrap the bullet train plans. The High Speed Rail Authority issued a statement:
"You can't make a comparison. High speed rail has been proven to be successful internationally. This is a conceptual idea that is years away."
If all goes as planned for the Hyperloop, Musk says it could take seven to 10 years for the first passengers to board it.
Musk says the Hyperloop would cost just $6 billion, a fraction of the High Speed Rail's roughly $70 billion price tag.
Musk is putting his design out in the public. He says he'll build a demo-model if no one adopts the design - a design that could prove to be a revolution in transportation, or a high-speed pipe dream.
The Associated Press contributed to this report.