ALCO S-2 — LLMpedia

ALCO S-2
NJPolselli (talk) · Public domain · source
Name	ALCO S-2
Powertype	Diesel-electric
Builder	American Locomotive Company
Builddate	1940–1950
Totalproduction	1,424
Aarwheels	B-B
Primemover	ALCO 539T
Poweroutput	1,000 hp
Operator	Various North American railroads

Contents

ALCO S-2 The ALCO S-2 is a 1,000-horsepower diesel-electric switcher built by the American Locomotive Company in the mid-20th century. It succeeded earlier road switchers and competed with designs from Electro-Motive Division, Baldwin Locomotive Works, and General Electric. The model saw widespread use on Class I carriers such as the Pennsylvania Railroad, New York Central Railroad, Baltimore and Ohio Railroad, and regional operators including the Missouri Pacific Railroad and Canadian National Railway.

Design and Development

ALCO developed the S-2 during a period shaped by companies like General Motors and the wartime demands tied to World War II industrial mobilization. Drawing on experience from earlier ALCO products and influenced by engineers associated with Schenectady Locomotive Works and managers from American Locomotive Company's Schenectady plant, the design used the inline six-cylinder ALCO 539T turbocharged prime mover. Competitors such as Electro-Motive Division's SW series and Baldwin’s VO models pushed ALCO to iterate on chassis layouts shared with manufacturers like Fairbanks-Morse and Westinghouse Electric Corporation. During development the S-2 incorporated advances parallel to those in EMD SW1 and GE 70-ton units used by entities like Union Pacific Railroad and Southern Pacific Railroad.

The S-2 employed a B-B wheel arrangement with AAR Type B trucks similar in concept to trucks used by General Electric and Baldwin Locomotive Works switchers. Its 539T prime mover produced 1,000 hp, paired with a GE traction motor setup comparable to traction packages supplied to Rock Island Line and Atchison, Topeka and Santa Fe Railway. The locomotive featured a short hood, long hood, and cab geometry resonant with ALCO yard locomotives sold to New Haven Railroad, Erie Railroad, and Chicago and North Western Transportation Company. Cooling systems and electrical components paralleled solutions implemented by American Locomotive Company on road-switcher types used by Nickel Plate Road and Boston and Maine Railroad. Braking systems met standards adopted by Interstate Commerce Commission regulations that affected carriers such as Lehigh Valley Railroad and Reading Company.

ALCO produced 1,424 S-2 units between 1940 and 1950, shipping orders to major buyers including Pennsylvania Railroad, New York Central Railroad, Baltimore and Ohio Railroad, Southern Railway (U.S.), and Canadian Pacific Railway. Variants included cab modifications and dynamic braking options employed by Conrail successors and industrial operators like U.S. Steel and Bethlehem Steel. Some units were rebuilt or repowered in programs run by shops at Illinois Central Railroad, Missouri-Kansas-Texas Railroad, and Seaboard Air Line Railroad; later rehabs mirrored practices at Norfolk and Western Railway and Chesapeake and Ohio Railway. Export and industrial derivatives found homes at ports run by entities such as Port of New York and New Jersey and industrial complexes serviced by United States Steel Corporation.

Operators deployed the S-2 in yard switching, local freight, and industrial service across networks like Penn Central Transportation Company, Amtrak (in selected transfer roles), and regional carriers including Central of New Jersey and Delaware and Hudson Railway. During the dieselization campaigns that followed World War II, the S-2 competed with purchases by Santa Fe, Southern Pacific Railroad, and Union Pacific Railroad, while shortline carriers such as Wheeling and Lake Erie Railway and St. Louis–San Francisco Railway also operated the model. The S-2 saw service on industrial spurs owned by Bethlehem Steel, U.S. Steel, and chemical producers served by DuPont facilities. Some units remained in service into the era of Conrail formation and subsequent regional restructuring that created carriers like Kansas City Southern and Iowa Pacific Holdings.

Numerous S-2s survive in museums and tourist operations, preserved by organizations such as the National Railroad Museum, Steamtown National Historic Site, and local historical societies in cities like Chicago, Buffalo, New York, and Denver. Excursion and tourist operators including Illinois Railway Museum, Pittsburgh & Lake Erie Railroad Historical Society, and North Carolina Transportation Museum maintain restored examples, while preserved industrial units appear at sites managed by Baltimore & Ohio Railroad Museum and California State Railroad Museum. Preservation efforts often involve component work informed by parts catalogs once supplied by General Electric, Westinghouse Electric Corporation, and ALCO remnants held by groups connected to American Locomotive Company heritage. Surviving S-2s are displayed alongside equipment from contemporaries such as EMD switchers, Baldwin Locomotive Works units, and GE industrial locomotives in collections referencing railroad histories like those of Pennsylvania Railroad, New York Central Railroad, Baltimore and Ohio Railroad, Southern Railway (U.S.), and Canadian National Railway.

Category:Diesel-electric locomotives