FRESNO, Calif. — On a median day, 1,000 employees head to dozens of development websites unfold over 119 miles throughout California’s huge Central Valley.

Their process is monumental: Construct the bridges and crossings designed to hold bullet trains that can type the spine of a $105 billion, 500-mile, high-speed rail system whose scale has drawn comparisons to the development of the interstate freeway system.

After all, 14 years after voters authorized an almost $10 billion bond to start out constructing the rail system that may whisk riders from Los Angeles to San Francisco at speeds of greater than 200 miles per hour, many California residents have lengthy since misplaced monitor of what’s being constructed the place, and when or if it can ever be accomplished.

But when, as President Biden mentioned in his State of the Union tackle, the nation is now coming into an “infrastructure decade,” there is no such thing as a extra dramatic testing floor — or extra cautionary spectacle — than California’s high-speed rail plan.

In 2008, when the bond measure handed, the venture symbolized the state’s ambition to construct and suppose huge. However within the years since then, the venture has grow to be one thing else: an alarming imaginative and prescient of a nation that appears incapable of finishing the transformative tasks essential to confront twenty first century challenges. The rail’s deliberate route and scope have modified on account of ballooning prices, political squabbles and authorized challenges.

“We simply have a basic downside in the USA of constructing massive tasks,” mentioned Yonah Freemark, a researcher with the City Institute who has been following the rail plan for greater than a decade. “And California’s high-speed rail is the biggest of the tasks.”

By no means have the instances for and in opposition to the hassle been so divergent.

However an eye-popping price ticket and basic questions on political assist are making a essential juncture for both reaching the venture’s full imaginative and prescient or leaving it in an costly limbo.

“The price of indecision on these tasks is gigantic,” mentioned Eric Eidlin, a scholar with the Mineta Transportation Institute at San Jose State College who has consulted on station planning efforts for the California Excessive-Pace Rail Authority.

Proponents say the venture has at all times been rather more than a prepare. If accomplished, they are saying, the system can be an financial tremendous charger connecting two of the nation’s greatest inhabitants facilities and a desperately wanted different to choked freeways and jammed airports as local weather change turns into an ever pressing problem.

“We’re the fifth largest financial system on the earth, and due to this fact I feel we now have to determine methods to do it,” mentioned Arnold Schwarzenegger, a Republican who as governor championed the 2008 bond measure. “Failure’s not an choice right here.”

Bent Flyvbjerg, a professor at Oxford College and the IT College of Copenhagen who has studied high-speed rail tasks all over the world, mentioned that such tasks almost at all times price rather more and take for much longer to construct than initially projected.

The distinction between high-speed rail tasks that limp alongside for many years and people who begin operating trains isn’t cash, he mentioned. It’s political power.

“The cash will likely be discovered if the political will is there,” he mentioned.

However political will inside California has ebbed as endurance amongst leaders has worn skinny. Essentially the most important turning level was the announcement three years in the past by Gov. Gavin Newsom in his first State of the State tackle that California would begin working a truncated part of the route that may run from Bakersfield to Merced within the state’s largely rural Central Valley.

That surprised supporters and fueled critics who believed he was publicly saying the total venture’s demise, though Mr. Newsom later mentioned the change in precedence wasn’t meant to preclude ending the total route.

Some state lawmakers, Republicans and Democrats alike, now say the hassle has grow to be flawed and unwieldy, maybe past saving. Critics say that rail officers are searching for a clean verify from state coffers, and that their timeline for completion is stretching unaccountably into the longer term.

“The venture is by all goal measures in misery,” mentioned Anthony Rendon, California Meeting Speaker, a Democrat. “Connecting the 2 largest city areas within the state is the very best factor we are able to do from an environmental standpoint and an financial improvement standpoint. To hyperlink two cities within the Central Valley would doom the venture.”

As an alternative of dedicating $4.2 billion of bond cash on this 12 months’s funds to, as Mr. Newsom put it, “end the job within the Central Valley,” Mr. Rendon mentioned he has requested the governor to withhold funds from the venture and spend extra on bettering present transit programs, notably within the Los Angeles space, which incorporates his district.

“What we’re targeted on is constructing ridership for an eventual high-speed rail venture, and the way in which you do that’s by engaged on the bookends,” he mentioned.

In a latest interview, Mr. Newsom mentioned his determination to prioritize the Central Valley section was based mostly on the calculation that the prospects for the total venture had been greatest if some a part of it had been working.

“The pivot was by no means to desert the imaginative and prescient,” he mentioned. “The long run remains to be there.”

He added that this 12 months’s funds proposal contains cash to proceed environmental and design work for the extensions past the Central Valley. “Nevertheless it requires federal sources — not completely, however primarily,” he mentioned.

A report by the California legislative analyst’s workplace notes that whereas the state’s legislature might determine to increase funding for the venture — together with a portion of cap-and-trade revenues by way of 2030 — it’s unclear the place the cash will come from to construct past the Central Valley section.

Consultants say that the fragmented nature of transportation planning within the nation has made the federal authorities hesitant to guess huge on new tasks quite than on fixing present programs. That’s layered over a nationwide political atmosphere wherein the looks of California boosterism generally is a legal responsibility, even for Democrats just like the president.

California’s high-speed rail will “get some federal funding now that there’s a Democratic administration in place and the infrastructure invoice is finished,” mentioned Jeff Davis, a senior fellow with the Eno Heart for Transportation, a nonpartisan analysis group. “However the federal authorities isn’t within the enterprise of making large infrastructure applications that disproportionately profit one state.”

Mr. Davis estimated that of a $36 billion “mom lode” of cash within the infrastructure regulation for states with intercity passenger rail, greater than half will go to the Northeast, leaving what’s left to be divvied up amongst tasks in different states. He mentioned that if California’s venture additionally competes for funding from smaller pots of cash within the regulation, like one designated for rail security, California might get $4 billion or $5 billion — “possibly.”

Nonetheless, proponents say that the concept of scraping collectively as a lot as $105 billion ought to be stacked in opposition to the prices of increasing highways and air service an equal quantity. The rail authority not too long ago put that quantity at near $200 billion, not together with the escalating prices of coping with local weather change, like preventing wildfires.

In states similar to Texas and Florida, personal companies have tried to capitalize on the necessity for sooner, greener rail programs in the USA.

However nothing approaches the magnitude of the California plan. Longtime supporters like former Gov. Jerry Brown describe high-speed rail as by far the very best climate-friendly transportation choice. They level with frustration and embarrassment to successes in nations across the globe — notably China, which has constructed greater than 20,000 miles of high-speed rail in about twenty years.

For Brian P. Kelly, who took over as chief government of the rail authority in early 2018, the one solution to get the venture achieved is to trudge ahead, regardless of the political climate.

He rattled off his duties forward as if he had been describing a day of errands: Get trains operating on the 170-mile Central Valley part. (Mr. Kelly mentioned he expects that to occur by the tip of the last decade.) Proceed with preparations for the extensions and end enhancements on both finish of the road. Then discover the cash to construct the remainder.

Within the meantime, the Central Valley — the implied “nowhere” when critics deride the venture as “a prepare to nowhere” — is altering quickly. The area’s main industries, like farming, are dealing with generational shifts. And households priced out of coastal cities are arriving in pursuit of comparatively reasonably priced housing, driving up prices and pushing out poorer residents as a part of an more and more acquainted cycle.

The prepare was at all times going to must go by way of the Central Valley. So whereas some native leaders have through the years vocally opposed the venture, many imagine the area ought to seize the alternatives the prepare might carry.

“We’re teetering on the sting,” mentioned Ashley Swearengin, a former mayor of Fresno who now leads the Central Valley Neighborhood Basis. “We might get it proper.”