NJ Transit spokesman John Durso Jr. says the person was taken to a hospital and is in surgery. His name has not been released.
Durso says the Raritan Valley Line train was headed to Newark with about 150 passengers aboard when the accident occurred at 5:25 a.m. Monday.
Durso says the passengers were transferred to another train.
The accident caused delays on Raritan Valley trains for about 90 minutes.
