Gov. Jerry Brown's ambitious plan to start building the nation's first dedicated high-speed rail line is set for a pivotal vote by the Legislature this week with some state lawmakers still skeptical about spending billions in the Central Valley. The Democratic governor is pushing lawmakers to authorize $2.7 billion in voter-approved state bonds for construction on the first 130-mile stretch of high-speed rail from Madera to Bakersfield. Brown has made the massive infrastructure project one of his priorities for the year and says the state has to act fast in order to capture billions of dollars in additional federal support. "Suck it in," Brown told an audience gathered last month for the 75th anniversary of the Golden Gate Bridge. "We got to build, we got to do it right." While Democratic leaders who control both houses of the Legislature support the bullet train, they concede that a legislative vote to authorize state bonds faces a tight vote, particularly in the Senate. Because Republicans oppose the project, at least 21 Democratic senators are needed to pass legislation on a simple majority vote. The project also faces GOP opposition in Congress. "We'll see where it goes," Senate President Pro Tem Darrell Steinberg of Sacramento said last week. Critics of high-speed rail say it's not clear where most of the construction funding will come from. They call the project too expensive and unnecessary. Recent polls show tepid support for a bullet train even though California voters authorized a total of $9 billion in what was intended to be the first round of bond financing back in 2008. Once complete, the $68 billion bullet train would connect Los Angeles with San Francisco. Dissenting Democratic lawmakers have suggested instead using bonds to improve existing rail systems within those densely populated areas. Sen. Mark DeSaulnier, chairman of the Senate Transportation and Housing Committee, said he won't support the plan because there's too much risk in placing the line in the Central Valley and too much uncertainty that the whole project will get done. He said with resources stretched, the state should focus on other needs such as education and health care. "Sometimes it's like a car you really wanted and it was a really good deal, and you're walking away from a good deal but you just can't afford it," said the lawmaker from Concord. "I've always said I was prepared to support high-speed rail done right," said Sen. Joe Simitian, D-Palo Alto, another skeptic. "But frankly the High-Speed Rail Authority has struggled to deliver a project that fits that description." Lawmakers are under pressure from labor groups that say the project is sorely needed because it will bring jobs, particularly to the Central Valley region that has higher-than-average unemployment. The Obama administration has threatened to rescind $3.3 billion in federal grants if the Legislature doesn't appropriate its share of funding. The governor is counting on those federal funds and the $2.7 billion in state bonds for a total of $6 billion to build the first segment. California was able to secure more than expected after Florida, Ohio and Wisconsin turned down federal money. Transportation Secretary Ray LaHood met with legislative leaders in Sacramento last month and told them not to delay the decision. The Federal Railway Administration has said the money must be used for the Central Valley segment. Steinberg, the Senate leader, said the Legislature will vote this week to authorize the state bond. Another $800 million or so will be dedicated for upgrades in Northern and Southern California. "I get the argument that to start in the Central Valley creates a risk because there's no guarantee of future funding," Steinberg said. "But here's the upside: There is a greater risk in not going forward. ... You will never know whether California could have led the national way in attracting more federal resources next year and the year after, much less private investment." The California High-Speed Rail Authority, which is managing the project, faces a September 2017 federal deadline to finish the first segment of the line in the Central Valley. Dan Richard, chairman of the authority, said the vote not only starts construction on high-speed rail in California but also authorizes financing to help electrify Caltrain, a San Jose-San Francisco commuter line, and upgrade Metrolink's lines in Southern California. "I'm absolutely convinced that the plan that we've put forth is the best plan given the resource limitations that we have," Richard said. "And it will move us forward towards an integrated intercity rail system with early investments in the bookends in the urban areas. It's a balanced plan." Legislative leaders have suggested that additional funding would next go toward extending high-speed rail from Bakersfield to Palmdale, which could link with regional rail systems into Los Angeles. Supporters say the project will bring roughly 20,000 jobs for the next five years. "This isn't just any vote," said Jim Earp, executive director of the California Alliance for Jobs, which represents union construction workers. "This is a watershed vote. It's the kind of vote that you remember what people do because a lot of folks' livelihoods depend upon what happens in Sacramento on this vote."