California Governor Jerry Brown (C) and his wife, Anne Gust, sign a railroad rail during a ceremony for the California High Speed Rail in Fresno, California on Tuesday. California officials broke ground on its ambitious but controversial high-speed rail project, marking another milestone for Brown and for foreign manufacturers waiting to bid on lucrative train contracts. REUTERS/Robert Galbraith

A groundbreaking ceremony for a California high-speed railway project is a symbolic moment for the state, but there are significant obstacles for the project, according to an urban planning expert.

"They have overcome quite a lot," Martin Wachs, a UCLA professor emeritus of urban planning, said in an interview with the Los Angeles Times, but "they certainly have enormous hurdles ahead of them".

"The largest is locating adequate funding to start a statewide system," he said.

California voters approved $10 billion in bonds for the railway in 2008, and the Obama administration added grants of $3.2 billion in 2012, but skepticism has surfaced as cost estimates have risen.

If the project follows the typical pattern of cost growth for large government projects, experts say it is likely to significantly exceed the $68 billion price tag, according to a story by the Times on Tuesday.

Officials in the construction industry said the delayed start for the project would require spending to be ratcheted up in order to comply with a federal funding stipulation. The requirement states that $2 billion in grants from Washington and $2 billion in state funding be spent by Oct 1, 2017.

Any unspent federal funds would have to be returned.

Dan Richard, chairman of the California High-Speed Rail Authority, told the newspaper that despite the challenges ahead, the authority is "very confident that this program is going to go forward".

Richard said a bridge over the Fresno River would be the first piece of major construction, but work might not start until April.

He also said billions of dollars more would be needed to complete the system, adding that real estate development rights along the route could provide some future cash flow for the project.

Governor Jerry Brown helped break ground on a 29-mile segment of the railway Tuesday, the first high-speed stretch attempted in the United States.

The groundbreaking was held at the future site of the high-speed train station in downtown Fresno. The initial segment will run from Madera to Fresno.

"The high-speed rail links us from the past to the future; from the south to the north," Brown said.

Robbie Hunter, director of California's building trades union council, told the Times that the project would generate 66,000 jobs a year over the next 16 years.

Requirements for the project include trains that can maintain speeds over 200 miles per hour, minimum seating capacity for 450 people, and a "buy America" provision, the authority said.

US-based SunGroup USA said in October that it had teamed with China's CNR Corp and its Tangshan Railway unit for a pitch. The group said it could supply California with up to 95 trains that can travel as fast as 220 mph.

By 2029, a trip from San Francisco to Los Angeles on the railway is expected to take less than three hours. The line will eventually extend to Sacramento and San Diego.

Brown has vowed to see the train system built, and in a 2013 trade mission to Shanghai, he courted Chinese investment.

An "ambitious construction schedule" could invite "unwise spending" for this project, said Wachs.

"Those projections are surrounded by uncertainty," Wachs said. "The public should understand that the uncertainties are much greater than the certainties. But our political process doesn't allow us to say, ‘We don't know what it will cost or how long it will take, but let's get started anyway.' "

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