Southern Pacific class AC-9
Encyclopedia
The AC-9 was one of two Southern Pacific Railroad
'sarticulated
steam locomotive
class that ran smokebox
forward after 1920. Twelve AC-9 class locomotives were built by Lima
in 1939 and were Southern Pacific's biggest steam engines. The AC-9s were partially streamlined (the only articulated steam engines to be so equipped), having skyline casings, and were equipped with coal tenders, unlike the cab forward
s. Wheel arrangement
was 2-8-8-4
, nickname "Yellowstone". Between 1939 and 1952, 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. In 1952, they were converted to burn oil instead of coal, and moved to the Southern Pacific's "Modoc" line between Sparks (Nevada) and Alturas (California), where they worked in freight service from 1953 till retirement in 1956. There is no preserved AC-9.
Southern Pacific Railroad
The Southern Pacific Transportation Company , earlier Southern Pacific Railroad and Southern Pacific Company, and usually simply called the Southern Pacific or Espee, was an American railroad....
'sarticulated
Articulated locomotive
Articulated locomotive usually means a steam locomotive with one or more engine units which can move independent of the main frame. This is done to allow a longer locomotive to negotiate tighter curves...
steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
class that ran smokebox
Smokebox
A smokebox is one of the major basic parts of a Steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is exhausted to the atmosphere through the chimney .To assist...
forward after 1920. Twelve AC-9 class locomotives were built by Lima
Lima Locomotive Works
Lima Locomotive Works was an American firm that manufactured railroad locomotives from the 1870s through the 1950s. The company took the most distinctive part of its name from its main shops location in Lima, Ohio. The shops were located between the Baltimore & Ohio's Cincinnati-Toledo main line...
in 1939 and were Southern Pacific's biggest steam engines. The AC-9s were partially streamlined (the only articulated steam engines to be so equipped), having skyline casings, and were equipped with coal tenders, unlike the cab forward
Cab forward
The term cab forward refers to various rail and road vehicle designs which place the driver's compartment substantially farther towards the front than is common practice.- Rail locomotives :...
s. Wheel arrangement
Wheel arrangement
In rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...
was 2-8-8-4
2-8-8-4
Under the Whyte notation for the classification of steam locomotives, a 2-8-8-4 is a steam locomotive with two leading wheels, two sets of eight driving wheels, and a four-wheel trailing truck.Other equivalent classifications are:...
, nickname "Yellowstone". Between 1939 and 1952, 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. In 1952, they were converted to burn oil instead of coal, and moved to the Southern Pacific's "Modoc" line between Sparks (Nevada) and Alturas (California), where they worked in freight service from 1953 till retirement in 1956. There is no preserved AC-9.