The agency spearheading California's efforts to build a high-speed train through the center of the state is plunging forward despite repeated warnings that it may be tens of billions of dollars short of the money needed to build and operate the system, records and interviews show.

"There is an air of unreality" about the project's $45 billion construction budget, a panel of experts warned the state Legislature last year.

It's a "big gamble" to start construction, the nonpartisan Legislative Analyst's Office warned in May, saying financing was "highly uncertain."

The project lacks "a disciplined business plan that makes any sense," says state Treasurer Bill Lockyer. He fears Wall Street won't invest anywhere near the $12 billion in private capital needed to build the system.

Undergirding the warnings, an inquiry by California Watch and the Orange County Register has found, is a tangle of related concerns:

The appointed officials who make up California's High-Speed Rail Authority say they will rely on $19 billion in federal aid to pay for the 800-mile system. But the legislative analyst says federal funding may amount to less than $4 billion – a $15 billion shortfall.

The rail authority's $45 billion construction estimate may be $22 billion too low, the legislative analyst says. Cost overruns of the sort that have afflicted other big U.S. projects could even drive the actual price above $200 billion, according to a critical study by a Stanford University professor.

The high-speed train's prospects for turning big profits are founded on ridership forecasts that are deeply flawed, two studies claim. Rather than making billions in profits, high-speed rail might actually "incur significant revenue shortfalls," a University of California at Berkeley study found.

The high-speed train's boosters say these concerns are unfounded or overblown. They say they are confident that sufficient funds will be found to build the system, which would connect Orange County and San Francisco via 220-mph trains.

Rail is the cheapest way to meet the transportation needs of California's burgeoning population, which could reach 50 million by 2030, advocates say.

Construction of the first leg, linking Fresno and Bakersfield, is set to begin next year. Eventually, trains would run all the way from Sacramento to San Diego.

The authority has based its cost estimates on mountains of studies, Deputy Executive Director Jeff Barker said. When the legislative analyst criticizes the authority's cost estimate, he said, it's "simply dumbing down the process."

He criticized the analyst's office for suggesting an overhaul of the project, saying that would mean delays guaranteed to increase the price.

"The sooner we build it," said rail authority Chairman Tom Umberg, "the less expensive it will be."

Plans start rolling

Japan, France and Spain are among the nations that have turned to high-speed rail to solve 21st-century transportation problems.

For a generation, transportation planners in California have looked to trains as well. In a state where the car is king, some saw rail as a way to break the cycle of building freeways to ease traffic gridlock, only to see the new roads fill up with cars. There were other foreseen benefits: Reining in urban sprawl. Reducing dependence on foreign oil. Cutting smog. And, of course, the economic boost that would come with a massive public works project.

In 2008, state voters approved $9.95 billion in bonds to begin building the system. Trains would be fast, frequent and cheap to ride, voters were told. Once the system was built, it would make money. No taxpayer subsidy would be allowed.