NJ Transit service is back up and running but riders are advised to expect delays this weekend after a fire in a train tunnel interrupted service for 12 hours on Friday.

Amtrak officials say a contractor was doing maintenance work around 1 a.m. when flames broke out, damaging overhead wires, signals, the track and equipment.

Five people were injured, two of them seriously.

The delays were so bad that some commuters abandoned the train all together.

NJ Transit is cross-honoring with the PATH at Newark Penn Station, Hoboken and 33rd Street.