A week after boasting about the state’s nascent high-speed rail in an open letter to President Trump, Gov. Jerry Brown lashed out at those who refuse to share his enthusiasm for the enterprise. In a speech to labor leaders Monday, according to the Los Angeles Times, Brown referred to criticisms of the project as “nonsense” and “bull—.”

The governor deserves credit for his no-bull commitment to an ambitious public work. The trouble is that, as evidenced by the latest plan to complete the San Francisco-to-Los Angeles line, the governor’s epithet could be applied to the endeavor’s shifting promises and price tags over the decade since voters approved it. False hopes have sown legitimate doubts about a worthwhile project.

A new draft business plan has the project costing $77 billion, nearly twice the $40 billion proposed to voters when they agreed to borrow $10 billion for it in 2008, and a 20 percent increase from what the High-Speed Rail Authority acknowledged just two years ago.

The plan also admits significant uncertainty about that, saying the cost could range from around $60 billion to nearly $100 billion. That depends partly on the vagaries of negotiating the mountains separating Los Angeles from the tracks under construction in the Central Valley, where the rail authority has already endured substantial overruns.

More troubling, it’s not clear where much of the funding will come from. The authority will need more state, federal or private money just to get from the Bay Area to the San Joaquin Valley. Brown said this week that doing so will require returning Democrats to power in Washington.

The project’s timetable also remains nebulous. While service all the way to Orange County was once promised by 2030, the latest plan only hopes to reach Bakersfield by then. Whether trains will ever travel between the two metropolises in less than three hours, another implicit promise of the ballot measure, is also an increasingly fraught question.

It’s heartening, at least, that the draft plan will face further scrutiny and that the state Capitol’s ruling Democrats recently joined Republicans in calling for an audit of the project. Despite its difficulties, the rail authority has cleared important obstacles, undertaken billions of dollars in construction and created hundreds of jobs. More importantly, the project can alleviate housing and transportation problems that dwarf it in scope. The challenge for legislators is to ensure that the train has a realistic, pragmatic plan to reach its destination and regain the public and political support it deserves.

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