Elon Musk’s proposed “hyperloop” system for whisking travelers between San Francisco and Los Angeles inside elevated tubes is technically feasible and should be expanded into a nationwide network, even though it would cost more per mile than initially thought.

That’s the conclusion of an unusual startup company formed to pursue the idea, Hyperloop Transportation Technologies. The startup, really a collection of unpaid volunteers with day jobs at some of Silicon Valley’s biggest companies, will release an update on its efforts Friday.

So far, the group has found no reason the hyperloop wouldn’t work. As envisioned by Musk, the serial entrepreneur behind Tesla Motors and SpaceX, the system would ferry passengers inside capsules hurtling through sealed tubes at more than 760 mph. Musk pitched the idea last year as an alternative to California’s planned high-speed rail system, which he said would look like Amtrak in comparison.

“We can say that it’s completely feasible,“ said Dirk Ahlborn, CEO of Hyperloop Transportation. “We know we can build it.“

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The company on Friday will release an interim feasibility study that fleshes out and refines Musk’s idea. Although Musk suggested the hyperloop could be built for $6 billion — far less than the high-speed rail system’s current $68 billion price tag — Ahlborn and his colleagues say the price would be more like $7 billion to $16 billion for the San Francisco-Los Angeles route.

Still, they argue that the hyperloop shouldn’t be confined to a single route. They suggest building a nationwide network, one that could revolutionize long-distance travel. The system would be fast enough and cheap enough, with tickets costing $20 to $30, that users could live in one metropolitan area and work in another, even if it’s hundreds of miles away.

“It’s not really so much about the technology at this point,“ Ahlborn said. “It’s more about how would we integrate the hyperloop into our daily lives.“

The startup is, in itself, unique.

While Musk came up with the idea, he openly invited other people to develop it, saying he was too busy with Tesla and SpaceX to do so himself.

Ahlborn and his colleagues have pursued the hyperloop idea as a huge crowdsourcing project. While Hyperloop Transportation Technologies is an incorporated company, none of its people are getting paid. Instead, the company’s “core team” consists of more than 100 professionals volunteering their time and expertise in return for a share of the company’s future profits, should any materialize.

The volunteers work at companies including Airbus, Boeing, Cisco Systems, Salesforce, Yahoo — and yes, Tesla and SpaceX. The head of its design team, Craig Hodgetts, teaches architecture and urban design at UCLA and has brought his students into the process, working on station designs. The company actively solicits strangers to critique its ideas and offer their expertise.

“We believe that people, when they get together and they’re passionate about something, money is not always necessary at the beginning,” Ahlborn said.

It will be at some point, however. Right now, the team is trying to refine the concept enough to know exactly how much a prototype would cost. At that point, the company will start raising money. Ahlborn said he has already been approached by venture capitalists interested in funding the project. So far, he has turned them down, he said.

“It’s too early — we don’t know how much money we’ll need,” he said. “It didn’t feel right to take on any money right now.“