It was disrupted earlier Monday due to an overhead wire problem.
NJT spokesman Joe Dee says the problem began around 6 a.m. near the Great Notch rail yard. Service was restored shortly before noon.
During the morning, NJT ran diesel service on the Montclair-Boonton line, taking passengers to Newark's Broad Street station or Hoboken, where they were able to transfer to New York-bound trains.