The Southern Pacific was an American Class I railroad network that existed from 1865 to 1996 and operated largely in the Western United States. The system was operated by various companies under the names Southern Pacific Railroad, Southern Pacific Company and Southern Pacific Transportation Company.
A 2-8-8-4 steam locomotive, under the Whyte notation, has two leading wheels, two sets of eight driving wheels, and a four-wheel trailing truck. The type was generally named the Yellowstone, a name given it by the first owner, the Northern Pacific Railway, whose lines ran near Yellowstone National Park. Seventy-two Yellowstone-type locomotives were built for four U.S. railroads.
Under the Whyte notation for the classification of steam locomotives, 4-8-4 represents the wheel arrangement of four leading wheels on two axles, eight powered and coupled driving wheels on four axles and four trailing wheels on two axles. The type was first used by the Northern Pacific Railway, and initially named the Northern Pacific, but railfans and railroad employees have shortened the name since its introduction. It is most-commonly known as a Northern.
The M1 was a class of steam locomotive of the Pennsylvania Railroad (PRR). It was a class of heavy mixed-traffic locomotives of the 4-8-2 "Mountain" arrangement, which uses four pairs of driving wheels with a four-wheel guiding truck in front for stability at speed and a two-wheel trailing truck to support the large firebox needed for sustained power. Although built for both passenger and freight work, they spent most of their service lives hauling heavy high-speed freight trains. Many PRR men counted the M1 class locomotives as the best steam locomotives the railroad ever owned.
Under the Whyte notation for the classification of steam locomotives, a 4-8-8-2 is a locomotive with four leading wheels, two sets of eight driving wheels, and a two-wheel trailing truck.
The term cab forward locomotive refers to various rail and road vehicle designs that place the driver's compartment substantially farther towards the front than is common practice.
The Southern Pacific GS-4 is a class of semi-streamlined 4-8-4 "Northern" type steam locomotive operated by the Southern Pacific Railroad (SP) from 1941 to 1958. A total of twenty-eight were built by the Lima Locomotive Works, numbered 4430 through 4457. GS stands for "Golden State" or "General Service."
The GS-6 is a class of semi-streamlined 4-8-4 "Northern" type steam locomotive operated by the Southern Pacific Railroad (SP) from 1943 to 1958 and the Western Pacific Railroad (WP) from 1943 to 1953. A total of sixteen were built by the Lima Locomotive Works, numbered 4460 through 4469 by SP and 481 through 486 by WP. GS stands for "Golden State" or "General Service".
The GS-5 was a class of streamlined 4-8-4 "Northern" type steam locomotive operated by the Southern Pacific Railroad (SP) from 1942 to 1958. A total of two were built by the Lima Locomotive Works, numbered 4458 and 4459. GS stands for "Golden State" or "General Service."
The GS-3 was a class of streamlined 4-8-4 "Northern" type steam locomotive operated by the Southern Pacific Railroad (SP) from 1938 to 1957. A total of fourteen were built by the Lima Locomotive Works, numbered 4416 through 4429. GS stands for "Golden State" or "General Service."
The GS-2 was a class of streamlined 4-8-4 "Northern" type steam locomotive operated by the Southern Pacific Railroad (SP) from 1937 to 1958. A total of six were built by the Lima Locomotive Works, numbered 4410 through 4415. GS stands for "Golden State" or "General Service."
Southern Pacific 4460 is the only surviving class "GS-6" steam locomotive, together with "GS-4" class Southern Pacific 4449, which is operational in excursion service. The GS-6 is a semi-streamlined 4-8-4 "Northern" type steam locomotive. GS stands for "Golden State" or "General Service". The locomotive was built by the Lima Locomotive Works (LLW) for the Southern Pacific Railroad (SP) in 1943. The GS-6 lacked side skirting and red and orange "Daylight" paint found on previous locomotives of the GS class and were painted black and silver instead. The War Production Board controlled locomotive manufacturers during World War II and had turned down Southern Pacific's order of fourteen new Daylight locomotives in 1942. Southern Pacific re-designed the new fleet based on the older GS-2s, only with 260 psi instead of 250 psi, an all-weather cab, and a new GS-4 style tender. The design was finally approved, but the War Production Board reassigned four to the smaller and power-starved Western Pacific Railroad. Their smaller size when compared to previous GS class locomotives and the fact that they were built during World War II earned them the nicknames "War Babies".
The Pennsylvania Railroad class Q1, #6130, was a single experimental steam locomotive designed for dual service. The locomotive entered service in 1942, and retired in 1949 after accumulating a relatively low 165,000 service miles.
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.
Southern Pacific Railroad's AC-10 class was the largest class of cab forward steam locomotives produced for the railroad. The design of this and the previous AC classes proved so successful for SP that the railroad began placing orders for the AC-10's successors, AC-11s, while Baldwin Locomotive Works was still busy building and delivering the AC-10s. Mechanically, the AC-10s were exceptionally similar to their immediate predecessors, the AC-8s.
Southern Pacific 4294 is a class "AC-12" 4-8-8-2 Cab forward type steam locomotive that was owned and operated by the Southern Pacific Railroad (SP). It was built by the Baldwin Locomotive Works in March 1944 and was used hauling SP's trains over the Sierra Nevada, often working on Donner Pass in California. Today it is preserved at the California State Railroad Museum (CSRM) in Sacramento, California.
Southern Pacific Railroad's MC-2 class of steam locomotives was the first class to be ordered by and built for Southern Pacific (SP) as cab forward locomotives. They were built in 1909 following the design of SP's MC-1 class built earlier that year. The success of this locomotive model led to the design and introduction of the AC class of 4-8-8-2 cab forward locomotives in the 1930s and 1940s.
Southern Pacific Railroad's AC-1 class of cab forward steam locomotives consisted of locomotives rebuilt from MC-1 and MC-2 class locomotives that were originally built by Baldwin Locomotive Works in 1909. The MC-2 class was the first class of locomotives built and delivered to SP as cab forward locomotives in late 1909. The AC-1 class was the first of the successful AC series of cab forward locomotives that numbered nearly 200 in total on the SP. Southern Pacific No. 4002 was rebuilt in June 1923 as a Cab Forward.
The AC-9 was one of two Southern Pacific Railroad's articulated steam locomotive classes that ran smokebox forward after 1920. Twelve AC-9 class locomotives were built by Lima in 1939 and were Southern Pacific's largest and heaviest steam engines, partly a consequence of low quality coal these engines were designed to burn.
Southern Pacific 786 is a preserved 2-8-2 "Mikado" type steam locomotive that was constructed at the American Locomotive Company's Brooks Works in New York. It was used to pull mainline freight trains by the Texas and New Orleans Railroad, a subsidiary of the Southern Pacific Railroad, until it was removed from service in 1955, and it was donated to the city of Austin, Texas the following year. Beginning in 1989, No. 786 was leased to the Austin Steam Train Association, who restored it to operating condition, and the locomotive was used to pull excursion trains on the Austin Western Railroad until 1999. Since 2000, crews have been performing an extensive rebuild on No. 786 to bring it back to service, and as of 2023, the rebuild continues to progress.
