SAN FRANCISCO  - California Governor Jerry Brown wants to move forward with building a statewide high-speed rail system seen costing nearly $100 billion, but lawmakers are nervous about approving bonds needed to lock in federal funds to get the project under way.

They are gagging at the rail system’s projected cost, which towers above its previous estimate of $43 billion, and are anxious about the uncertain outlook for federal and private-sector dollars needed to lay hundreds of miles of train tracks between California’s far-flung metropolitan areas.

Like many in the Legislature, Democratic Assemblyman Jared Huffman supports the concept of high-speed rail. But he has sticker shock: “Anybody who is paying attention has to be very sobered by the numbers.”

Lawmakers are also concerned about the California High-Speed Rail Authority’s oversight of the project. Its chief executive resigned on Thursday and the chairman of its board also stepped down, though he will remain on the board. Dan Richard, a board member appointed by Brown, has been nominated as new chairman.

Additionally, lawmakers are acutely aware of buyer’s remorse among many voters over the project with state finances still under pressure. California faces a $9.2 billion budget gap.

Voters approved nearly $10 billion of general obligation debt in 2008 to help build the rail system.