(AP) - The race to build the world's first "hyperloop" is on.
Three Southern California companies want to erect tracks to test how well the speed-of-sound transportation concept works in the real world.
Billionaire entrepreneur Elon Musk breathed life into the hyperloop idea in 2013, when he proposed a network of elevated tubes to transport capsules of people or cargo over long distances. Top speed: more than 700 mph.
On Tuesday, Musk's SpaceX rocket launching firm said construction firm AECOM would build a one-mile track at SpaceX headquarters near Los Angeles. By summer's end, the track will host prototype capsules that emerge from a design competition this weekend at Texas A&M University.
Two startup companies also plan tracks. One is building near Las Vegas, and the other is eyeing California's Central Valley.