Although its carbody and frame are externally identical to the EMD SD50, the SD60 contains the all-new EMD 710 Series Diesel engine and rides on newly designed HT-C trucks. Conrail purchased 3 of EMD's demonstrators, 1,4,2 (6840 - 6942) in August 1984. An additional 25 units were purchased in 1989. After this purchase, Conrail did not buy a single EMD locomotive until 1993.