The head of the Metropolitan Transit Authority has admitted to federal safety officials that its Metro-North traffic control staff worked seven days straight — for weeks — when several accidents, including one fatal, occurred last year.

The New York Daily News reports MTA chairman Tom Prendergast told investigators with the National Transportation Safety Board that over-worked staffers were in charge of directing commuter trains. He blamed personnel shortages.

The NTSB is investigating five major Metro-North incidents, including a derailment in the Bronx last December that killed four passengers. Earlier that same year, a track worker was struck and killed by a train in West Haven, Conn.

In his interview with investigators, Prendergast called the personnel shortage one of the agency’s biggest challenges. 

"You can't just step into the position. You have to know the system inside out," said William Henderson, executive director of Permanent Citizens Advisory Committee to the MTA. "It's not something you can make a short term fix to. It really takes some time to cultivate the people that are there."

Prendergast, who has been head of the MTA since June 2013, also said he was surprised at the state of the agency when he started the job.

“The decay was a lot worse than you would have expected it to be,” Prendergast said.

The investigations are ongoing.