Chicago's O’Hare International Airport could be connected to the CBD by a high-speed link shuttling travellers between two new underground stations in just 12 minutes at speeds up to 240kph.

The US$1 billion system will mark the debut of 'Loop' technology created by Tesla founder Elon Musk – a scaled-down version of Musk's more ambitious Hyperloop ultra-high-speed transport system.

Built by Musk's Boring Company, the Chicago Loop transit system will use "autonomous electric skates," analogous to train carriages to carry eight to 16 passengers apiece.

The pods will be made by Tesla, although Musk leaves room for the possibility of cars using the system, too.

The system will run underground, giving Musk’s venture a chance to show off its tunnel-boring technology. The company has said it’s faster and cheaper than other subterranean projects. “Tunnel construction and operation will be silent, invisible and imperceptible at the surface,” the company said.

Musk hasn’t given up on his original vision for an ultra-high-speed transport system. At a news conference with Mayor Rahm Emanuel on Thursday, Musk said the Loop "will ultimately transition to the Hyperloop system."

That technology would be designed for longer distances, like, say, Chicago to New York. “That’s where you’d want to make use of the Hyperloop,” Musk said.

While Musk won the bid to build a high-speed express train between Chicago's airport and downtown, it’s not quite a signed contract yet – but if the parties proceed, it will give Musk a chance to prove parts of his untested technology.

A success in Chicago would give Boring Co. considerable credibility as it tries to move ahead on other projects, including service within Los Angeles and a planned system between Washington, D.C., and New York City. Chicago is bearing no financial responsibility for the project, Emanuel said. Boring Co. will finance the entire construction cost itself.

Funding the effort didn’t appear to be a concern for Musk. “I don’t really have much trouble raising money, historically,” he said. “So I don’t expect too much trouble doing so in this situation.”