Train service has resumed on Amtrak's Northeast Corridor after a three-hour delay.
The low-voltage problem halted Northeast Corridor, North Jersey Coast Line and Midtown Direct trains into and out of Penn Station, NJ Transit spokesman Dan Stessel said.
The Long Island Rail Road was not affected, the railroad said.
Record snowfall over the weekend has snarled LIRR traffic during the past few days, but trains Wednesday were running normally.
In a message published Tuesday on the railroad's Web site, LIRR president Helena Williams acknowledged "a difficult week for the LIRR" and thanked customers for their patience. "Please know that hundreds of LIRR employees worked around the clock before, during and after the storm to keep the railroad operating," she wrote.
The power problems on Amtrak lines halted trains and stranded commuters.
Some trains were stranded just outside Penn, while others were stuck between Newark and New York City.
Stessel said there was enough electricity to power the lights and heat on the trains, but not the engines.
PATH trains and Port Authority buses were honoring NJ Transit rail passes.
- With Sophia Chang