A 58-year-old man was struck and killed by an outbound commuter train on Newton Street in Brighton Saturday night, transportation officials said.
The man was allegedly trespassing on the tracks when the accident happened, around 6:30 p.m.
There were about 500 people on the commuter rail, according to Massachusetts Bay Commuter Railroad Company spokesman.
The track was closed and passengers were delayed for nearly three hours while police investigated the incident.
The track reopened shortly before 9 p.m.
Details on why the man was on the tracks were not released.