Former Vice President Joe Biden said he's been a "champion" for rail and mass transit.
"I've been pushing really hard for mass transit and for rail. We can take millions of vehicles off the road if we have high-speed rail," he said. "I've been the champion of that for 25 years."
Biden added that in order for new rail lines to be successful, they have to be as fast and as cost efficient as driving.
"It would literally take millions of vehicles off the road. But you have to have a rail system that makes people say, 'If I get on that rail, I will get there as fast as I would have gotten had I driven and I can afford to do it relative to the coast of my driving.'"