The current price tag is listed as $68 billion, but it has fluctuated wildly. California's High-Speed Rail Authority says it is still cheaper than building dozens of new airport runways and highways to accommodate a state population expected to hit 46 million by 2035.
— Who is paying for it:
The state agency that oversees the project has nearly $10 billion in voter-approved bonds for rail construction and improvements to existing lines, and $3.2 billion in federal financing for the first 130 miles. But no private investors have stepped forward yet, and it is unclear where the rest of the financing will come from. A court case that could delay the project hinges on the state's funding plan.
— Where will it go:
Construction will start in the Central Valley, a 30-mile stretch from Madera to Fresno. In future years, the rail line will stretch westward to San Jose and south to Palmdale and the San Fernando Valley. There are currently no plans to link the train lines to Sacramento or San Diego.
— When will it be built:
Shovels will be in the ground "within a few months," rail officials say.
Construction work has been repeatedly delayed, and officials face a deadline to finish the first leg by 2017 or risk losing the federal money. Officials initially said it would start last year, then delayed it to summer 2013 and currently say "within a few months." However, engineering, surveying and excavation work has begun.
The high-speed rail business plan says trains will run between the greater Los Angeles area and the San Francisco Bay Area by 2029.