Work will begin today on the nation's first bullet-train line, meant to eventually connect Los Angeles and San Francisco, even though funding concerns and political opposition have raised questions as to whether the project will ever be completed, The Associated Press reported.

Fresh into his fourth term as California governor, Democrat Jerry Brown -- who has declared the high-speed rail a priority for the state -- will lead the groundbreaking for the first stretch of the route at what would be the future downtown station in Fresno.

The train would transport travelers between California's largest metropolitan areas at 200 mph, reducing travel times between Los Angeles and San Francisco to less than three hours. The 520 miles of track needed for that stretch are supposed to be completed by 2029, but only partial funding has been secured for the $68 billion project.

Dan Richard, the chairman of the California High-Speed Rail Authority, acknowledged the challenges faced by his agency but said he was confident the high-speed system would be built.

"The voters are going to get exactly what they asked for," he said. "We have never ever stepped away from that vision, not one inch."

In 2008, Californians had approved a nearly $10 billion bond for the project, and the federal government has since contributed another $3.3 billion. A portion of greenhouse-gas fees collected under the state's cap-and-trade program will also go toward the rail line, though they are only expected to generate between $250 million and $1 billion annually, the Los Angeles Times noted.

Making matters even more complicated is experts predict the project will likely exceed its estimated price point, as the the $68 billion figure is "surrounded by uncertainty," according to Martin Wachs, a UCLA professor emeritus of urban planning.

"The public should understand that the uncertainties are much greater than the certainties," Wachs said. "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.'"

Republicans, now in control of Congress, meanwhile, have shown little love for the project and vowed to cut off additional funds. Local Republican lawmakers, likewise, have been critical of the California High-Speed Rail Authority.

"They haven't solved their problems yet. Their business plan doesn't show it is viable," state Rep. Kevin McCarthy said. "It could become like the skeleton of an unfinished building, and they will have to stop."