The wires were damaged earlier Wednesday in Cecil County.
It is not clear yet what caused the damage.
An Amtrak spokesperson told Action News "Nothing we've seen indicates any connection to terrorism or sabotage. We're focusing more on a mechanical or possibly weather-related cause."
At Philadelphia's 30th Street Station, travelers had no choice but to wait it out.
"Mass confusion. Nobody giving any information," said Geoffrey Kreiss of Washington, D.C.
"I am sitting here working and staying in touch- trying to stay ahead of the game," said Angie Britt of Alexandria, Virginia.
Some people were more anxious than others.
"We've been here since Sunday of last week for a business seminar, so I am very anxious to get back home. Now we don't know when we're going to get back home," said Renaldo Johnson of Bristol, Connecticut.
Amtrak said crews will continue working through the night to restore full service in time for the morning rush hour on Thursday.