Southern Pacific class AC-8

Southern Pacific Railroad's AC-8 class of cab forward steam locomotives was the fifth of SP's 4-8-8-2 classes. They were built by Baldwin Locomotive Works in 1939.

Southern Pacific class AC-8
Type and origin
Power typeSteam
BuilderBaldwin Locomotive Works
Serial number62265 62292
Build dateJuly–October 1939
Gauge4 ft 8 12 in (1,435 mm) standard gauge
Driver dia.63 in (1,600 mm)
Adhesive weight531,700 lb (241,200 kg; 241.2 t)
Loco weight657,900 lb (298,400 kg; 298.4 t)
Boiler pressure250 psi (1.7 MPa)
Feedwater heater6SA Worthington
Cylinder size24 in × 32 in (610 mm × 813 mm) (bore × stroke)
Performance figures
Tractive effort124,300 lbf (553 kN)
OperatorsSouthern Pacific Railroad
Number in class28
Numbers4177 4204
First runAugust 18, 1939
Retired1955 1957
DispositionAll scrapped

The AC-8s were the first to receive the larger redesigned cab windows as standard equipment that were retrofitted onto earlier AC class locomotives. The locomotives were only slightly larger than their AC-7 predecessors.

On November 19, 1941, No. 4193 caught on fire. It was carrying a freight train passing through Santa Susana Pass near Los Angeles. The train caught on fire because of a failure to shut off the oil feed. It was carrying 96 cars (not including its tender) and a caboose. A knuckle on the front end of the seventy-fifth car was broken when the accident occurred. Read more on the cab forward section. On May 3, 1941, No. 4199 suffered a boiler explosion at Cooper, California.

The first AC-8 entered service on August 18, 1939, and the last on November 26, 1939. Number 4173 was first to be retired from active service on September 2, 1954, while 4172 was the last on January 9, 1958. All of these locomotives were scrapped, beginning with 4155 on November 26, 1954, and ending with 4172 on April 24, 1959.


  • Diebert, Timothy S. & Strapac, Joseph A. (1987). Southern Pacific Company Steam Locomotive Conpendium. Shade Tree Books. ISBN 0-930742-12-5.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.