Amtrak service was suspended for about two hours between Washington and cities to the northeast on Monday night because of an electrical problem, authorities said.
Amtrak said about 9:15 p.m. that Northeast Corridor service was halted south of Philadelphia as a result of a problem with the overhead power system near Wilmington, Del.
Trains were being held at Union Station in Washington and at the 30th Street Station in Philadelphia, Amtrak said.
At 11:30 p.m. Amtrak said service had been restored. It said residual delays were to be expected as crews worked to clear congestion.