Southern Pacific class AC-9

Southern Pacific AC-9
Type and origin
Power typeSteam
BuilderLima Locomotive Works
Serial number7765–7776
Build date1939
Total produced12
Specifications
Configuration:
​
 • Whyte2-8-8-4
 • UIC(1′D)D2′ h4
Gauge4 ft 8+1⁄2 in (1,435 mm)
Driver dia.63+1⁄2 in (1,613 mm)
Axle load66,400 lb (30.1 tonnes)
Adhesive weight522,200 lb (236.9 tonnes)
Loco weight677,200 lb (307.2 tonnes)
Total weight998,000 lb (453 t)
Fuel typeOil (originally coal)
Fuel capacity28 short tons (25 t; 25 long tons)
Water cap.22,100 US gallons (84,000 L; 18,400 imp gal)
Firebox:​
 • Grate area139.5 sq ft (12.96 m2)
Boiler pressure250 psi (1.72 MPa)
Heating surface6,918 sq ft (642.7 m2)
Superheater:
​
 • Heating area2,831 sq ft (263.0 m2)
CylindersFour (simple articulated)
Cylinder size24 in × 32 in (610 mm × 813 mm)
Valve gearWalschaerts
Performance figures
Tractive effort123,364 lbf (548.75 kN)
Career
OperatorsSouthern Pacific Company
ClassAC-9
Numbers3800–3811
NicknamesReverse cab forward
DispositionAll scrapped

The AC-9 was a class of articulated steam locomotive operated by Southern Pacific Railroad. The twelve AC-9 class locomotives were purchased from Lima in 1939 and were specifically designed to burn low grade bituminous coal mined in New Mexico.[1]

The AC-9s were partially streamlined (the only articulated steam engines to be so equipped), having "skyline casings" inspired by Lima's GS series of 4-8-4's, also made for Southern Pacific, and were equipped with coal tenders, unlike the cab forwards. The wheel arrangement was 2-8-8-4, which was nicknamed "Yellowstone".

Between 1939 and 1953, all the twelve AC-9 engines were in service between Tucumcari, New Mexico, El Paso, Texas, and Tucson, Arizona, where they mainly pulled freight trains and occasionally also passenger trains such as the Golden State Limited. Between May and August 1950, they were converted to burn oil instead of coal, and in spring 1953 eleven of them moved to Southern Pacific's Modoc line between Sparks, Nevada, and Alturas, California, where they worked in freight service from 1953 until retirement in early summer 1956.

All examples were scrapped between 1953 and 1956.[1]

References

  1. ^ a b Morrison, Tom (2018). The American Steam Locomotive in the Twentieth Century. McFarland and Company Inc. pp. 1693–1696. ISBN 978-1476679006.


This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.