Project leaders estimate it will still need an additional $100 billion to finish what voters were originally pitched in 2008: a bullet train that runs between San Francisco and Los Angeles. A timeline on its completion has not been set as the authority waits for environmental clearances for those segments. "It's been tough to fund a project with something that has an expiration date," Kelly noted. "We're doing it in building blocks. We're giving you the portions we think we can get done with the funding we have."