The 'reinforcement rail' on concrete is probably one side of a mobile gantry crane setup. This looks to be at a Boston & Maine team track near Lechmere Square. The crossing is not unguarded: there are typical B&M crossing gates on all 4 corners of the crossing. They may be controlled from that shack on the opposite side of the crossing, a little right of center. There appears to be a freight house and more team track area next to the trolley line bridge in the background, and that tall building is probably the freight office. It just has that 'B&M look'.
