On day four of commuter hell following Monday's "minor derailment" at Penn Station, Amtrak President & CEO Wick Moorman held a press conference in which he personally apologized to all those impacted by the chaos and promised that full service would be restored by rush hour on Friday morning.

During the briefing, the executive confirmed that both derailments—the one involving an Amtrak Acela on March 24th and the second involving a NJ transit train on April 3rd—were caused by tracks problems in Penn Station. The first was due to a mismatch between two pieces of rail, while this week's derailment came as a result of defective wood ties, he said. Amtrak owns the tracks at Penn Station, and leases them to NJ Transit and the LIRR.

"I have visited with our crew and we expect to have all tracks at NYP accessible by Friday morning." - Wick Moorman https://t.co/Y77ML0EOYo pic.twitter.com/Dg3SbWnKt7 — Amtrak Northeast (@AmtrakNEC) April 6, 2017

The executive also admitted that Amtrak was previously aware that the weak timbers responsible for Monday's derailment were in need of replacement.

"We had notation that these timbers needed to be replaced," Moorman said. "We clearly didn't have the understanding that there was going to be an imminent failure. We knew at some point this year the maintenance program would be getting to it. We got it wrong."

The admission came hours after Governor Chris Christie announced that the state would be withholding funding from Amtrak until an "an independent examination" verifies that the corridor is in a state of good repair. The governor also said that he's directed the state's attorney general to consider suing to recoup the $62 million that NJ transit has paid to Amtrak for track use.

Asked about the sternly worded letter, Moorman conceded that the governor had a right to be upset, but noted that "withdrawing funding is not going to solve any of the problems."

In addition to inspections from the state, the executive said that he would be personally leading a comprehensive review of infrastructure conditions at all Amtrak stations.

"We have a lot of work to do," Moorman said. "I don't want to tell you that this is going to be easy."

