Derided by critics as pie in the sky, the train would use magnetic levitation technology to carry passengers from Disneyland to Las Vegas in well under two hours, traveling at speeds of up to 300 mph. It would be the first MagLev system in the U.S.
The money is the largest cash infusion in the project's nearly 20-year history. It will pay for environmental studies for the first leg of the project.
The money had been delayed by a drafting error in Congress' 2005 highway bill, which was corrected along with some other changes by the legislation signed Friday by Bush. The delay had allowed a competing and cheaper diesel-electric plan to emerge as an alternative, but with the money now freed up supporters hope to move forward with the MagLev plan.
The train is meant to ease traffic on increasingly clogged Interstate 15, the main route for the millions of Southern Californians who make the 250-plus-mile drive to Las Vegas each year. There is no train on the route - Amtrak's Desert Wind between Los Angeles and Las Vegas was canceled in 1997 because of low ridership.
Senate Majority Leader Harry Reid, D-Nev., praised passage of the law, saying the MagLev project "will safely and efficiently move people between Southern California and Las Vegas."