President Donald Trump canceled nearly $1 billion in federal funding for the high-speed rail project in 2019, during his first term. The Biden administration later restored the funding and, in December 2023, allocated $3.3 billion more.

The transportation secretary, Sean Duffy, said the government would conduct a “compliance review” on a $3.1 billion grant, potentially threatening the viability of the troubled project.

The Trump administration has launched an investigation into California’s high-speed rail project in what could be the first step in clawing back the $4 billion promised by the Biden administration to build out the first section of the line, from Merced to Bakersfield.

Duffy, speaking at Union Station in Los Angeles on Thursday morning, said the Federal Railroad Administration will review the rail project and its leadership.

While U.S. Transportation Secretary Sean Duffy questioned the cross-state high-speed rail project, he praised the Las Vegas-to-Los Angeles effort.

The Federal Railroad Administration initiated a review of California's 400-mile high-speed rail project aimed at connecting Los Angeles to San Francisco following concerns voiced by the Trump Administration,

Republicans have long targeted high-speed rail, despite its popularity with a majority of Californians. U.S. Rep. Kevin Kiley, who appeared with Duffy and introduced legislation in December to defund it, blasted the railway as “the worst public infrastructure failure in U.S. history.”

Secretary of Transportation Sean Duffy said the California high-speed rail project will continue to cost taxpayers billions of dollars with no definitive timeline for completion.