Southern Pacific class AC-7

Southern Pacific class AC-7
Type and origin
Power type Steam
Builder Baldwin Locomotive Works
Serial number 61952-61963, 62038-62051
Build date January–August 1937
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 514,800 lb (233.5 t)
Locomotive weight 639,800 lb (290.2 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-7
Number in class 26
Number(s) 4151 – 4176
First run February 8, 1937
Retired 1954 – 1958
Disposition scrapped

Southern Pacific Railroad's AC-7 class of cab forward steam locomotives was the fourth class of the 4-8-8-2 locomotives purchased by Southern Pacific (SP). The locomotives were built by Baldwin Locomotive Works and shared many of the same characteristics of previous AC class locomotives.

The AC-7s were only slightly larger than their AC-6 predecessors, but they included larger tenders and a beveled cab front in contrast to the earlier classes' flat cab front. In the early 1940s, the majority of the class received larger cab windows of a design that would become standard with the AC-8 class.

In April 1937, locomotive number 4162 was pulled aside for a series of publicity photos at SP's Sacramento, California, shops. It was posed alongside the railroad's first locomotive, C. P. Huntington a diminutive 4-2-4T, especially when compared to 4162.

The AC-7 class locomotives were all removed from active service between 1954 and 1958, and they were all scrapped shortly after their removal from service. The first to be scrapped was 4155 on November 26, 1954, while the last was 4172 on April 24, 1959.

References