All trains between New York and Philadelphia were suspended on Wednesday evening because of fallen electrical wires in Kearny, N.J., that power the trains at Pennsylvania Station, according to Amtrak.

The power outage stopped Amtrak and New Jersey Transit trains, an Amtrak spokesman, Jason Abrams, said in an email. Long Island Rail Road and subway trains that stop at Penn Station were unaffected, according to a spokeswoman for the Metropolitan Transportation Authority, which runs both services.

In Kearny, New Jersey Transit is building a replacement for the 114-year-old Portal Bridge, but it is not clear if the problem is related to that work, Mr. Abrams said.

The power outage started at 5:05 p.m., Mr. Abrams said, adding that crews were working to restore power. As of 7:15 p.m., it was unclear when train service would resume, he said.

Riders on New Jersey Transit will have their tickets and passes honored on PATH trains, which are running between Manhattan and New Jersey, according to a spokesman for New Jersey Transit. To avoid Penn Station, travelers also may take a ferry to Hoboken, where six New Jersey Transit lines offer service.

This is a developing story.