New Jersey Transit spokesman John Durso Jr. says the 11-car train came to a stop in Metuchen on its way to New York City around 7:40 a.m.
The passengers were taken to the platform, where they could board another train.
The downed wire is causing delays of up to 60 minutes on the busy Northeast Corridor line between Trenton and Princeton Junction.
Trains into New York City are suspended at New Brunswick, Edison and Metuchen.
New York-bound trains between Rahway and New York City are running up to 30 minutes behind schedule.