SACRAMENTO -- More than $11 billion in taxpayer money is promised so far for high-speed rail in California, including at least $252 million that already has been spent.

But the government's gamble won't pay off unless private investors jump on board the $40-plus billion project -- and so far no one has pledged a dime.

If the money doesn't come, the state and federal governments risk sinking billions of dollars into a rail line that never gets finished.

"This could be the greatest thing that ever happens to the state, or a real disaster," said state Sen. Alan Lowenthal, D-Long Beach, who has taken a lead oversight role.

Fears of failure grew recently when state Treasurer Bill Lockyer told the San Diego Union-Tribune editorial board that Wall Street is "convinced that no one can finance the routes from L.A. to the Bay Area, that it just will never work economically, certainly in the foreseeable future."

In an interview with The Bee, he softened those comments some, saying investors are "skeptical," but that "these are just preliminary comments" made before anyone has spent time "making a disciplined investment decision."

The High Speed Rail Authority's plan assumes companies will cover up to $12 billion of the $42.6 billion first phase, which would connect San Francisco to Anaheim and Los Angeles via 220 mph trains that stop in Fresno. Valley business leaders are counting on the train to pump new economic life into the region, potentially including new jobs for a maintenance yard.

The rail authority is moving forward on the assumption that investors will engage once the state completes environmental reviews, finalizes the route and buys up all the rights of way -- tasks not scheduled for completion until 2014.

The authority expects it might even have to start construction on some of the segments before investors step up. The estimated phase-one completion date is in the 2019-20 fiscal year.

"We've said all along that the private investment in the project is going to come toward the end," said Jeff Barker, a rail authority spokesman. "Before the private sector is going to put private money into this, they're going to want to see that it's real."

In one potential scenario, construction companies, rail-car makers, train operators and financial institutions could form a consortium. In return for an investment, they would get a cut on profits during a 30-year lease, plus control of the system -- including the power to set fares, Barker said.

Thirty companies responded to a survey of interest in 2008, including construction company Balfour Beatty, rail equipment maker Bombardier and financial firm Goldman Sachs. Public pension funds such as the California Public Employees Retirement System also could be targeted.

But inking deals is no easy task, said Richard Little, director of the Keston Institute for Public Finance and Infrastructure Policy at the University of Southern California.

The "private sector is real hard on these kinds of things," he said. "They don't have to invest in high-speed rail. They want to put their money into something that's going to give them the best return."

Historically, major transportation projects have been paid for with state and federal money and no up-front private investment. But with construction costs outpacing federal commitments, project sponsors are increasingly turning to so-called public-private partnerships, in which companies cover a portion of construction costs in exchange for future revenues, notes the rail authority's business plan.