EMD SW1

EMD SW1
Hugh Llewelyn · CC BY-SA 2.0 · source
Name	EMD SW1
Powertype	Diesel-electric
Builder	Electro-Motive Division
Builddate	1939–1953
Totalproduction	661
AARwheels	B-B
Primemover	EMD 6-567A/B/C
Poweroutput	600 hp
Tractiveeffort	42,000 lbf
Operator	Various North American railroads, industrial operators, military

EMD SW1

The EMD SW1 is a 600-horsepower diesel-electric switcher built by the Electro-Motive Division of General Motors during the mid-20th century. The model played a central role in yard switching and industrial service across North America and appears in preservation rosters, museum collections, and photographic surveys of Pennsylvania Railroad, New York Central Railroad, Atchison, Topeka and Santa Fe Railway, Baltimore and Ohio Railroad, and Union Pacific Railroad equipment. Its development reflects dieselization trends following World War II that involved General Motors, ALCO, Baldwin Locomotive Works, American Locomotive Company, and other contemporaries.

Introduction and Overview

The SW1 emerged from Electro-Motive Division's lineage that included earlier switchers and road switcher projects tied to figures such as E. H. Harriman-era freight expansion and corporate leaders at General Motors who directed wartime and postwar motive power policy. Railroads including the Southern Pacific Railroad, Chicago, Burlington and Quincy Railroad, Milwaukee Road, and Great Northern Railway ordered SW1s for hump yard duty, local freight, and industrial plant switching. The model complements other EMD products like the EMD NW2, EMD S-series, and EMD F-unit families and competed with switchers from Baldwin and Alco during a period influenced by procurement programs of the United States Army Transportation Corps and freight standardization initiatives.

Design and Technical Specifications

The SW1 used a two-axle B-B wheel arrangement with traction motors and a frame derived from EMD road-switcher practice. Its 6-cylinder 567-series prime mover, variants 6-567A, 6-567B, or 6-567C, produced 600 horsepower driving a generator and DC traction motors supplied by EMD. Key components and systems paralleled those on contemporaneous EMD GP7, EMD SD7, and EMD FT models, including Blomberg-style trucks in some rebuilds, Westinghouse and General Electric air brake equipment, and standardized electrical cabinets familiar to servicing personnel from Alco RS-1 and Baldwin VO-660 maintenance records. Dimensions, weight distribution, and hood-unit visibility addressed requirements set by yards operated by railroads such as New Haven Railroad, Lehigh Valley Railroad, and Erie Railroad. The SW1's cooling, lubrication, and fuel systems reflect practices codified by industrial standards overseen by agencies like the Interstate Commerce Commission during the era of its manufacture.

Production and Variants

Produced between 1939 and 1953, 661 units were built at EMD facilities and by General Motors' subsidiaries, with early prewar demonstrators tied to orders from the Atchison, Topeka and Santa Fe Railway and wartime allocations associated with agencies including the United States War Department. Variants included cab and hood modifications, radio-equipped yard units for railroads like the Chicago and North Western Transportation Company and Southern Railway (U.S.), and rebuilt examples retrofitted with later 567B or 567C components similar to retrofit programs on EMD SW7 and EMD SW9 fleets. Some were sold to industrial operators such as U.S. Steel, Bethlehem Steel Corporation, and pulp-and-paper companies serving facilities in Puget Sound and the Great Lakes region. Rebuilds and renumberings frequently connect SW1s to regional short lines like the Delaware and Hudson Railway's successors and modern heritage railways operating former freight trackage from the Conrail breakup.

Operational History

SW1s served in hump yards, classification facilities, waterfront terminals, military depots, and industrial plants across the United States and Canada, working for carriers including Canadian National Railway, Canadian Pacific Railway, Missouri Pacific Railroad, Illinois Central Railroad, and Rock Island Line. Their service records intersect with episodes such as postwar freight expansion, labor actions affecting Brotherhood of Locomotive Engineers and Trainmen negotiations, and the consolidation era culminating in systems like Conrail and later CSX Transportation and Norfolk Southern Railway. Units were notable in photographic documentation by railroad photographers active in regions like Northeast United States railroad photography and featured in trade journals published by organizations like American Railway Engineering and Maintenance-of-Way Association.

Preservation and Survivors

Numerous SW1 examples survive in museums, tourist operations, and static displays, preserved by institutions such as the Illinois Railway Museum, California State Railroad Museum, Heber Valley Railroad, and local historical societies tied to cities like Chicago, Buffalo, New York, and Portland, Oregon. Preserved units appear in rosters of heritage railroads including the Narrow Gauge Railroad Museum and excursion operators that collaborate with preservation groups like the Railway & Locomotive Historical Society and National Railway Historical Society. Restorations often employ parts interchange from EMD families and support from volunteer corps modeled on efforts by Operation Lifesaver-affiliated educational programs. Surviving SW1s provide tangible links to mid-20th-century motive power transitions documented in archives maintained by the Smithsonian Institution, Library of Congress, and regional transportation museums.

Category:Electro-Motive Diesel locomotives Category:Diesel-electric locomotives of the United States