Working the hump in Union Pacific’s Davidson Yard in Fort Worth, Texas, on October 16, 2011, is SD40N 1613 and a pair of RP20BDs, 2626 and 2613. “SD40N” is a new designation for some SD40-2s on the UP, and this one was built as UP 3372. The RP20BDs were constructed by RPI from old GE B23-7 and B30-7 engines, usually of those built for the Missouri Pacific.
