Erie Lackawanna bought both EMD’s standard SD45 (No. 3602, right) and the lengthened version designated SDP45 (3639, left). The extra space at the rear of the SDP45 was intended to house a steam generator for passenger service, and the additional space between the trucks accommodated a tank for fuel oil and one for water for the steam generator. EL’s SDPs were strictly freight engines, the extra space between the trucks being devoted entirely to an extra-large fuel tank.
Louis A. Marre collection