A man was struck and killed by a Rockaway Park bound L train at the Morgan Avenue stop last night as he attempted to cross the tracks. According to the NYPD, an MTA motorman said Brooklyn resident Grzegoiz Bartosiewicz, 42, was crossing from the northbound tracks to the southbound tracks at 9:50 p.m., and was trying to climb onto the southbound platform when he was hit. Both trains in the station stopped, and the power to the tracks was shut off. The MTA confirmed that Bartosiewicz died at the scene.