The body of a 40-year-old Salem, N.H., man was found on commuter rail tracks at North Station Sunday morning, according to the MBTA. The body was found at 4 a.m. on Track 5, said MBTA spokesman Joe Pesaturo in an e-mail. The man’s “injuries were consistent with those typically caused by a train strike,” he said. The MBTA did not release the man’s name. There was no train activity on the track at the time, Pesaturo said, and it was unclear when the man died; an investigation was underway.