Trains are moving again between New York City and Philadelphia.
New Jersey Transit spokeswoman Courtney Carroll says service has been restored after low-voltage problems forced Amtrak and NJ Transit trains to stop at the nearest station.
Carroll says NJ Transit trains are facing delays of up to an hour on the Northeast Corridor and North Jersey Coast Line.
Midtown Direct trains have resumed operating to and from New York.
It's not known what caused the problem. Calls seeking comment from Amtrak have not been returned.
The problem comes two days after a transformer fire in New Jersey halted rail service for several hours.