Mayor Rahm Emanuel's office confirmed reports it is negotiating with Elon Musk's The Boring Co. to build a high-speed rail line from downtown to O'Hare International Airport. The Boring Co. won a bidding process from four competing bids, and estimates the system would cost under $1B to build.

One factor in the city's selection of The Boring Co. for the project is Musk's promise to foot the bill, the Chicago Tribune reports. Both parties have declined to discuss costs or negotiations.

Emanuel is also taking a gamble on Musk's still-unproven tunneling technology over more traditional high-speed rail options touted as a solution to cutting the current 40- to 45-minute average time it takes the Blue Line 'L' to travel from downtown to O'Hare. The new proposal is for a slower system Musk calls "Loop," which would ferry up to 16 passengers from Block 37 to O'Hare in 12 minutes, at speeds of over 100 mph, in autonomous vehicles. Passengers would pay between $20 and $25 per ride.

The ongoing negotiations will include finalizing a route. The Boring Co.'s preliminary route would run from Randolph Street west to the Kennedy expressway, then run northwest under Milwaukee and Elston avenues before heading west to O'Hare, where it would end near the new international terminal as part of the airport's $8.5B expansion.

In exchange for building the new system, The Boring Co. would keep all revenue from transit fees and ads. Emanuel is seeking a long-term lease from Boring for the system.