The victims, all male, were on a bridge near Dover in northwest New Jersey that is closed to the public, The Star-Ledger of Newark reported. They were hit around 7 p.m. by a westbound commuter train that had just departed Dover for Hackettstown.
The two injured men were taken by helicopter to Morristown Medical Center, John Durso, a spokesman for the transit agency, said.
Durso said the bridge, which crosses the Rockaway River, has fences to keep pedestrians off and signs warning the rail line is an active one.
While some witnesses said there were two other people in the group on the bridge, Durso said transit police searched the area without finding anyone.
The victims have not been identified pending notification of their families.
Rail service on the line west of Dover was suspended after the crash.
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