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

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.”

The Trump administration is once again targeting California's controversial high-speed rail project, with federal transportation officials on Thursday announcing an investigation and possible withdrawal of about $4 billion in federal funding.