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.

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