California’s efforts to build the nation’s first high-speed rail network, which has seen its projected costs nearly triple since it was initiated in 2008, may see $4 billion of previously approved funds eliminated following a review of the program by the Transportation Department.

Earlier this month, President Donald Trump indicated his displeasure with the project, falsely claiming it had “hundreds of billions of dollars of cost overruns.” In fact, the total projected cost of the 400-mile network is pegged at about $100 billion, of which $15.7 billion has been spent–using only about $3 billion of federal money so far. Still, newly appointed Transportation Secretary Sean Duffy said that both the rising cost of the railway, which has climbed from an initial estimate of about $33 billion, and its fuzzy timeline for completion make it a bad continuing bet for U.S. taxpayers.

“I'm going to exercise my authority as the Secretary of Transportation to direct the Federal Railroad Administration, or FRA, to initiate a compliance review of funding to the California High-Speed Rail Authority,” Duffy said at a press briefing at Union Station in downtown Los Angeles on Thursday. “This is going to help determine whether billions of dollars in taxpayer money should remain committed to California's High-Speed Rail. We're going to look at whether California High-Speed Rail has actually complied with the agreements that they've signed with the federal government.”

The loss of any funding for the project at this time would risk the state’s ability to open the initial 171-mile segment running through the Central Valley, connecting cities including Merced, Fresno and Bakersfield. That first portion, which currently employs about 15,000 workers, was targeted to open in the early 2030s. There’s no firm timeline for when connections to San Francisco and Los Angeles would be completed, owing to the need to secure at least $70 billion of additional funding.

“We welcome this investigation and the opportunity to work with our federal partners,” said Ian Choudri, CEO of the state rail authority. “With multiple independent federal and state audits completed, every dollar is accounted for, and we stand by the progress and impact of this project.”

While Duffy and Trump aren’t fans of the state project, billionaire Wes Eden’s $12 billion Brightline West bullet train, which aims to connect Las Vegas to suburban Los Angeles with the help of a $3 billion federal grant, appears to remain in favor with the new administration. A private bond offering to cover the remaining cost of the Brightline project priced today, valuing the offering at $2.5 billion.

It “seems like a project that is worthy of investment,” Duffy said. “But this project, if completed, 400 miles from LA to San Francisco at best it'll cost $106 billion. Most people will say that is a rosy estimate. There’s no way it’s going to be completed for $106 billion.”

As Duffy completed his remarks, a few dozen protesters gathered near the press conference at the train station, holding signs in favor of the state rail project and chanting anti-Trump, anti-Musk and anti-Duffy slogans.

Coincidentally, Canadian Prime Minister Justin Trudeau said on Thursday that his government intended to provide $2.7 billion to help build a high-speed rail line to connect cities including Toronto, Ottawa, Montreal and Quebec City.