The first hours of Sunday morning were grim: At around 3 a.m., a man who investigators say “appeared to be walking between cars” on a northbound Q fell onto the tracks at the Prince Street station and was crushed by the train. Later, at around 4 a.m., a man was killed by on oncoming Metro-North train on the tracks near 67th Street. Though a Metro-North spokesman said that the victim had been “trespassing,” the accident marked yet another unfortunate event in the commuter rail’s very bad year.