Southern Pacific class AC-11

Southern Pacific class AC-11
SP 4274 leading an excursion train out of Reno, Nevada, on December 1, 1957.
Power type	Steam
Builder	Baldwin Locomotive Works
Serial number	64677 – 64706
Build date	November 1942 – April 1943
Configuration	4-8-8-2
Track 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)
Tractive effort	124,300 lbf (553 kN)
Career	Southern Pacific Railroad
Class	AC-11
Number	4245 – 4274
First run	November 24, 1942
Retired	1954 – 1958
Disposition	scrapped

Southern Pacific Railroad's AC-11 class of cab forward steam locomotives was the seventh class of 4-8-8-2 locomotives ordered by Southern Pacific (SP) from Baldwin Locomotive Works; SP was so pleased with the AC-10 class built a year earlier that the railroad began placing orders for AC-11s while the AC-10s were still being built and delivered. They were built between November 1942 and April 1943, closely resembling the AC-10s.

The first AC-11, number 4245, entered service on November 24, 1942, and the last, 4274, on May 9, 1943. SP used these locomotives for between 12 and 15 years, with the last retirements from this class occurring on September 24, 1958. Shortly after their retirement, the AC-11s were scrapped, with the last, number 4262, on August 27, 1959.

References [edit]

• Diebert, Timothy S. and Strapac, Joseph A. (1987). Southern Pacific Company Steam Locomotive Conpendium. Shade Tree Books. ISBN 0-930742-12-5.