Southern Pacific class AC-10

Southern Pacific class AC-10
Type and origin
Power type Steam
Builder Baldwin Locomotive Works
Serial number 64287 – 64326
Build date January–July 1942
Specifications
Configuration 4-8-8-2
Gauge 4 ft 8 1⁄2 in (1,435 mm)
Driver diameter 63 in (1,600 mm)
Weight on drivers 531,700 lb (241.2 t)
Locomotive weight 657,900 lb (298.4 t)
Boiler pressure 250 psi (1.7 MPa)
Feedwater heater 6SA Worthington
Cylinder size 24 in × 32 in (610 mm × 810 mm) (bore × stroke)
Performance figures
Tractive effort 124,300 lbf (553 kN)
Career
Operator(s) Southern Pacific Railroad
Class AC-10
Number in class 40
Number(s) 4205 – 4244
First run February 17, 1942
Retired 1955 – 1958
Disposition all scrapped

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