Southern Pacific Railroad's AC-10 class was the largest class of cab forward steam locomotives produced for the railroad. The design of this and the previous AC classes proved so successful for SP that the railroad began placing orders for the AC-10's successors, AC-11s, while Baldwin Locomotive Works was still busy building and delivering the AC-10s. Mechanically, the AC-10s were exceptionally similar to their immediate predecessors, the AC-8s. The first AC-10, number 4205, entered service on February 17, 1942, and the last, 4244, on August 19, 1942. SP used these locomotives for about fifteen years, with the first retirements of this class (three locomotives) occurring on April 5, 1955 and the last (three more of the class) on September 24, 1958. The locomotives were scrapped soon after they were retired, with the last one, number 4243, scrapped on August 7, 1959. References AC-10 4-8-8-2 locomotives Baldwin locomotives Simple articulated locomotives Railway locomotives introduced in 1942 Steam locomotives of the United States Scrapped locomotives Standard gauge locomotives of the United States Cab forward steam locomotives Freight locomotives