The problem with a government audit, as any fearful bureaucrat knows, is that teams of number crunchers poring over the books always turn up embarrassing details. Unleash the dogs, and they’ll dig up a bone.

In the case of California’s wobbly high-speed rail plan, it’s especially true with lots to analyze, double-check and unearth. Two state lawmakers — one a fan and the other a foe — want the full audit treatment for the project. It’s almost certain to underscore the cost overruns and delays that go with any mention of the Bay Area-to-Southern California rail idea.

Yet a serious, independent audit could save, not spike, a promising concept that voters backed a decade ago and the state badly needs to modernize travel. The sore points and failures that an audit probably will find could produce the right responses to get the idea back on track.

The audit request comes at a do-or-die moment. Gov. Jerry Brown played up his support in his State of the State address last week, saying, “I like trains, and I like high-speed trains even better.” He’s sending in a new chief executive, Brian Kelly, who previously ran the state’s transportation agency, to come up with a new business plan. Construction continues on the first stretch running through 119 miles of Central Valley farmland.

But plans for the $65 billion line are way beyond original estimates. The first phase cost is jumping by $3 billion to $10.6 billion, a nasty surprise because the flat landscape was expected to make it easier to build. The timeline for the rest of the system, including a section connecting San Francisco and Bakersfield and the final miles to Los Angeles, could be delayed beyond a promised 2029 deadline.

While Brown remains a booster, this is his final year in office. Among his potential successors, high-speed rail doesn’t enjoy the same love and affection. The candidates are offering conditional support or outright avoidance in talking about an issue Brown prizes. Killing a project this big sounds inconceivable, but voters aren’t hearing what the next governor has in mind: full speed ahead, cancellation or a sawed-off version.

The audit could clarify the major issues and offer guidance. Ways to save money, trim costs and get the system rolling more quickly should be explored. On the flip side, there needs to be a dose of reality in understanding the complexity and scale of a 500-mile system that crosses mountains, runs through cities and operates at an all-new technical level.

The audit request comes from state Sen. Jim Beall, a San Jose Democrat who chairs his chamber’s transportation panel. He’s long backed more money for transit projects and sided with high-speed rail, which will have tracks through his city.

His stature is especially significant because past audit requests from anti-train Republicans have gone nowhere in the Democrat-controlled Legislature.

Joining him is Jim Patterson, a Republican Assemblyman. He’s a former mayor of Fresno, a major stop on the rail line, and a longtime opponent of the project he considers wasteful.

This joint parentage could remove doubts that the audit will be a put-up job for either side in the debate. Far from appearing as a parliamentary backstabbing, an audit could serve up what high-speed rail needs: a focus on problems, independent evaluation and an implied path forward.

Cost overruns are nothing new for public works projects that are needed. The Bay Bridge rebuild zoomed in price to $6.5 billion, far beyond original estimates.

If the system can be built, it will confer enormous benefits on the state. Faster travel times between north and south are only part of an idea that can speed up business connections, link housing to jobs and avoid a dependence on cars and jets in a far-flung state. A state with 40 million residents can’t rely on freeways and airports.

These benefits will happen only if there’s public and political enthusiasm that the bullet train doesn’t have now. An audit, worrisome as it is to insiders, can help a promising and needed project.

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