On my way home via MBCR 231 (5:15 Boston-Haverhill) just after we cleared Lawrence St and Rt 495 and over Marblehead St. I looked out of the window to what looked to be the light of a GP-40 2W. Well my thoughts were correct as GP40-2W 5XX went by us with a single covered hopper on the Number 1? Track heading into Boston. Any ideas?