U.S. Secretary of Transportation Sean Duffy said Thursday he would launch a compliance review of the $4 billion in federal funds allocated to California’s high-speed rail project — the ambitious, but long-delayed plan to send bullet trains from Los Angeles to downtown San Francisco.

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.