AUSTIN, Texas — Entrepreneur Elon Musk says Texas is atop his list to build a five-mile-long test track for his conceptual Hyperloop  project that involves shooting capsules full of people through elevated tubes at the speed of sound.

"Texas is the leading candidate," Musk told the Texas Transportation Forum in Austin on Thursday.

He said he discussed the idea with associates the previous evening and envisions teams from universities or companies using the test track to develop designs for the project he revealed in 2013 in California.

"It sounded good last night after a couple of drinks," he laughed, describing his management style as "shoot from the hip."

Musk said he was "just figuring out" a timetable and wasn't certain how much the five-mile loop track would cost.

"There's no quid pro quo here," he said. "We're not asking for any money from the state.

"If somebody wants to chip in, I'm not going to stop them."

Musk already has a rocket plant near Waco for his SpaceX company and is building a rocket launch facility outside Brownsville.

When he announced his Hyperloop  two years ago, it was described as shooting capsules containing people at the speed of sound through elevated tubes connecting Los Angeles and San Francisco. The 400-mile trip would take about 30 minutes. He estimated two years ago that such a project would cost $6 billion.

Technology already exists for capsules to float on a thin cushion of air and draw on magnetic attractions and solar power to zoom through a nearly air-free tube. The lack of wind resistance could allow for the supersonic speeds.