NEW YORK (AP) – Commuters heading into New York City are facing delays after an empty commuter train derailed inside Penn Station.

New Jersey Transit spokeswoman Penny Bassett says an Amtrak crew was moving a NJ Transit train out of a railyard when some of the cars derailed Wednesday. The derailment occurred on Track 4, where repair work that started earlier this summer is still underway.

NJ Transit’s Northeast Corridor, North Jersey Coast, Montclair-Boonton and Midtown Direct trains are running up to 20 minutes behind schedule. It’s unknown how the derailment will affect Amtrak, Long Island Rail Road and the city’s subway lines.

Bassett says workers hope to move the cars out of the way to reopen the tracks.

Trains have been operating under revised schedules this summer while Amtrak conducts extensive repairs at Penn Station.

Before the work began in early July, New York Gov. Andrew Cuomo warned that commuters could be in for a “summer of hell.”