Southern Pacific class AC-3

Southern Pacific class AC-3

Type and origin Power type Steam

Specifications Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Driver diameter 57 in (1,448 mm) Adhesive weight 440,800 lb (199,900 kg) Loco weight 481,200 lb (218,300 kg) Boiler pressure 210 psi (1,400 kPa) Feedwater heater 4¼-BL Worthington Cylinder size 22 in × 30 in (559 mm × 762 mm) in dia × stroke

Performance figures Tractive effort 90,940 lbf (404,500 N)

Career Operators Southern Pacific Railroad Class AC-3 Number in class 20 Numbers 4029 – 4048 Retired 1948 – 1949 Disposition scrapped

Southern Pacific Railroad's AC-3 class of steam locomotive was the last cab forward design based on the 2-8-8-2 wheel arrangement. All 20 locomotives in this class were rebuilds from MC-6 class locomotives originally built by Baldwin Locomotive Works in 1912 and 1913. The rebuilds all took place in the late 1920s at Southern Pacific's Sacramento shops.

After the rebuilds, these locomotives were used through World War II. The first to be retired from active service were numbers 4040 and 4045, both on October 21, 1946; the last to be retired was number 4032 on August 8, 1949. All of this class were scrapped soon after retirement.