The incident resulted in service being suspended in both directions on NJ Transit's Bergen County line.
The man was hit by a Hoboken bound train on the Bergen County Line, near the Glen Rock-Fair Lawn border, just after 7 a.m.
Witnesses said the man walked in front of the train.
It was the second person to be fatally struck by a NJ Transit train Thursday.
At around midnight, a 26-year-old man stepped in front of a Hoboken-bound NJ Transit train along the Pascack Valley Line, near the Emerson-Westwood border.