SpaceX has selected 124 teams of mostly college student engineers to participate in a Hyperloop Pod competition at the end of January. The teams will present their concepts for pods, which will then compete on a test track next summer in front of judges from SpaceX, Tesla, and universities.

The hyperloop, as outlined by Elon Musk two years ago, would involve a pod or capsule moving at nearly the speed of sound inside a tube elevated above the ground. This kind of track system could provide rapid transportation between cities 1,500 km or less apart, Musk said, after which supersonic aircraft would probably be faster or cheaper. Passengers might travel from Los Angeles to San Francisco in just 30 minutes, according to Musk. The idea was hailed as visionary by some, but others have criticized it for being far from practical.

Although Musk has said he is focused on launching rockets with SpaceX and building electric cars with Tesla, he has nonetheless sought to nurture the project along by developing a functional prototype. To that end, he invited young engineers to propose ideas for a pod. The teams, from 27 US states and 20 countries, will have their concepts judged on January 29 and 30 at Texas A&M University in College Station.

Those selected to advance will then need to find sponsors and build prototypes for testing on a 1-mile test track near the SpaceX headquarters in Hawthorne, California, next summer. “It’s not really known whether this is a solvable problem,” Gregory Chamitoff, an astronaut and professor of engineering at Texas A&M, told Ars. “This may transform the way we travel around the future. We don’t know. This is one of the problems where if you don’t tell the students it’s impossible they’ll figure out a way to do it.”

Chamitoff said engineering students have really responded to the challenge because it poses a real-world problem. Additionally, he said, SpaceX has “this magical ability” to inspire because it has big dreams when it comes to spaceflight, and it has already done a lot in terms of flying the Falcon 9 rocket and supplying the International Space Station.

Many questions have been raised about the financial viability of a new transportation system, but Musk has argued that the pods and linear motors to propel them along the tracks will be relatively inexpensive, costing “several hundred million dollars.” The tube itself, rising above the ground on pylons with a narrow footprint roughly equal to that of a telephone pole, would cost several billion dollars to construct alongside highways between major cities, he acknowledges.

However, Musk believes the hyperloop makes more sense when compared to high speed rails. “A ground based high speed rail system by comparison needs up to a 100-foot-wide swath of dedicated land to build up foundations for both directions,” he wrote. “It is also noisy, with nothing to contain the sound, and needs unsightly protective fencing to prevent animals, people, or vehicles from getting onto the track.”

Musk said the hyperloop idea grew out of his disappointment with California’s massive, $67 billion high-speed rail project that would connect San Francisco and Los Angeles and cut the travel time to 2 hours and 40 minutes. That initiative, supported by a $10 billion public bond issue, was too slow, too costly, and not forward-thinking enough for Musk.

“The underlying motive for a statewide mass transit system is a good one,” he wrote. “It would be great to have an alternative to flying or driving, but obviously only if it is actually better than flying or driving. The train in question would be both slower, more expensive to operate (if unsubsidized), and less safe by two orders of magnitude than flying, so why would anyone use it?”

Now, in about six weeks, some physical manifestations of Musk's ideas will be first to be put to the test.