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EMD GP7

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Article Genealogy
Parent: Electro-Motive Division Hop 4
Expansion Funnel Raw 82 → Dedup 17 → NER 14 → Enqueued 7
1. Extracted82
2. After dedup17 (None)
3. After NER14 (None)
Rejected: 3 (not NE: 3)
4. Enqueued7 (None)
Similarity rejected: 6
EMD GP7
EMD GP7
CC BY-SA 2.0 · source
NameEMD GP7
PowertypeDiesel-electric
BuilderElectro-Motive Division
Builddate1949–1954
Totalproduction2,734
AarwheelsB-B
PrimemoverEMD 16-567B
CylindersV16
Poweroutput1,500 hp
Tractiveeffortstarting 61,200 lbf

EMD GP7 The EMD GP7 is a diesel-electric road switcher produced by Electro-Motive Division of General Motors between 1949 and 1954. Designed to replace steam locomotives for freight and branch-line service, it became widely adopted by North American railroads, shortlines, and industrial operators. The model influenced subsequent designs and entered service with major carriers including Pennsylvania Railroad, Atchison, Topeka and Santa Fe Railway, Southern Pacific Transportation Company, New York Central Railroad, and Union Pacific Railroad.

Development and Design

EMD developed the GP7 during a period when Alco, Baldwin Locomotive Works, Fairbanks-Morse, American Locomotive Company, and International Harvester were competing for postwar diesel orders. The GP7 featured a hood unit layout derived from the earlier FT and F-units, incorporating a 16-cylinder EMD 567 two-stroke diesel engine similar to those used in E-series locomotives for higher reliability. Designers at EMD consulted with operating executives from Chicago and North Western Transportation Company, Milwaukee Road, Great Northern Railway, Baltimore and Ohio Railroad, and Erie Railroad to optimize visibility, maintenance access, and braking systems. The GP7's road switcher concept echoed experiments by Rock Island Line and design trends from Canadian National Railway and Canadian Pacific Railway.

Production and Variants

Production of the GP7 generated orders from major carriers such as Chicago, Burlington and Quincy Railroad, St. Louis–San Francisco Railway, Missouri Pacific Railroad, New York, New Haven and Hartford Railroad, and Seaboard Air Line Railroad. EMD and its Montreal subsidiary GMD built units for Canadian National and Canadian Pacific markets. Variants included the GP7B with generators for multiple-unit control ordered by Penn Central Transportation Company and GP7M rebuilds by Illinois Central Railroad and Southern Railway. Rebuild programs by Conrail, Norfolk Southern Railway, CSX Transportation, and Kansas City Southern Railway produced GP7R, GP8, GP9M and GP10 derivatives. Export and industrial adaptations served Brazil, Mexico, Chile, and Australia railways, with customization for Atchison, Topeka and Santa Fe branch lines and Western Maryland Railway needs.

Technical Specifications

The GP7 used the 16-cylinder EMD 567B prime mover delivering 1,500 horsepower, a Roots-type supercharger, and direct current generators compatible with Multiple-unit train control systems specified by Association of American Railroads. The B-B wheel arrangement used AAR Type B trucks similar to those on EMD GP9 and EMD GP18 designs. Braking systems incorporated Westinghouse-style air brakes common to New York Central practice and influence from Pennsylvania Railroad standards. The locomotive's electrical equipment shared components with EMD SW-series and EMD F7 units, while fuel capacity and cooling systems were tailored to requirements set by Southern Pacific and Union Pacific operating divisions. Weight distribution and tractive effort suited mixed freight duties on grades found on Sierra Nevada and Appalachian Mountains routes.

Service History

GP7s entered service on mainlines and branch lines for carriers including Baltimore and Ohio Railroad, Long Island Rail Road, Central of Georgia Railway, Missouri–Kansas–Texas Railroad, and Wabash Railroad. They hauled freight, performed yard switching, and operated passenger extras for roads like Illinois Central and Pennsylvania Railroad during dieselization campaigns that mirrored transitions seen on Southern Railway and Northern Pacific Railway. Reassignment to shortlines and industrial users followed retirements, with preserved units appearing in heritage operations associated with National Railway Historical Society, Pennsylvania Historical and Museum Commission, and railroad museums inspired by Age of Steam preservation movements. Overhaul and parts sourcing involved suppliers connected to General Electric and aftermarket shops formed by former employees of Electro-Motive Division.

Preservation and Surviving Units

Numerous GP7s survive in museums, tourist railroads, and active shortlines, with examples owned by institutions such as the Illinois Railway Museum, California State Railroad Museum, National Railroad Museum, California Trolley and Railroad Corporation, and Age of Steam Roundhouse. Several units are operational on excursions run by Railroad Museum of Pennsylvania, Colorado Railroad Museum, New York Museum of Transportation, Texas State Railroad, and Durango and Silverton Narrow Gauge Railroad affiliates. Preservation groups including the Railway & Locomotive Historical Society, Center for Railroad Photography and Art, and regional historical societies maintain rosters and restoration programs. International survivors appear in collections at Museo Ferroviario de Santiago, Museo Nacional del Ferrocarril (Argentina), and private operators in Australia.

Category:Electro-Motive Division locomotives Category:B-B locomotives