EMD GP40

EMD GP40 is a four-axle diesel-electric road locomotive built in the United States by Electro-Motive Division between 1965 and 1971. It served major North American railroads including Union Pacific Railroad, Penn Central Transportation Company, Southern Pacific Transportation Company, Burlington Northern Railroad, and Conrail, becoming a mainstay for freight service on mainline and branch routes. The design emphasized increased horsepower, modular maintenance, and compatibility with contemporary EMD controls and braking systems.

Design and Development

The GP40 evolved from earlier EMD models such as the EMD GP35 and the EMD GP38, incorporating the two-stroke 16-cylinder EMD 645 engine to generate 3,000 horsepower comparable to contemporaries like the General Electric U30C and the Alco C628. Development work at Electro-Motive Division in La Grange, Illinois reflected input from Class I railroads including Atchison, Topeka and Santa Fe Railway and Norfolk and Western Railway to improve reliability for heavy merchandise trains and unit coal trains operated by Seaboard System Railroad predecessors. The locomotive adopted a standard B-B truck arrangement similar to that used by EMD GP9 rebuild programs, while integrating features such as a modular electrical cabinet inspired by EMD SD40 practice and improved dynamic braking for grades in regions served by Denver and Rio Grande Western Railroad and Southern Railway (U.S.).

Technical Specifications

The GP40 is powered by an EMD 16-cylinder, two-stroke 645E3 prime mover coupled to a main generator and four GE- or EMD-built traction motors; the arrangement provided continuous tractive effort suitable for tonnage demands on lines operated by Chessie System predecessors. The locomotive used standard EMD electrical controls compatible with multiple-unit operation alongside EMD GP7, EMD GP9, and EMD SD40 locomotives, and featured a 3,000 hp rating, 4-stroke-derived 645 family improvements, and a fuel capacity tailored for long-haul assignments similar to those on Union Pacific Railroad mainlines. Braking systems conformed to AAR standards used by Penn Central Transportation Company and later Conrail, while the locomotive’s carbody and trucks allowed interchange on routes administered by Canadian National Railway and Canadian Pacific Railway after resale and rebuilds.

Production and Variants

EMD produced 1,221 GP40s at facilities in La Grange, Illinois and London, Ontario, with production spanning 1965–1971; buyers included Burlington Northern Railroad, Chicago and North Western Transportation Company, Southern Pacific Transportation Company, and Seaboard Air Line Railroad. Variants and related models included the high-horsepower GP40-2 successor, rebuilt versions such as GP40-2R programs executed by Illinois Central Railroad and Conrail workshops, and export or cab-modified units sold to regional carriers like Missouri Pacific Railroad and Chicago, Burlington and Quincy Railroad. Many units received modifications and rebuilds through programs at shops like Illinois Central Gulf facilities, and specialty conversions for passenger service were done for operators comparable to Amtrak on specific demonstrator efforts.

Service History

GP40s entered revenue service hauling manifest freights, intermodal consists, and local turns across networks operated by Southern Pacific Transportation Company, Atchison, Topeka and Santa Fe Railway, Burlington Northern Railroad, and Norfolk Southern Railway predecessors. During the railroad consolidations that produced entities such as Conrail and CSX Transportation, GP40s were traded, renumbered, and repurposed for yard and secondary mainline work; numerous examples were later rebuilt into GP40-2 standards or used in shortline operations for carriers like Iowa Interstate Railroad and Genesee & Wyoming Inc. The model’s ruggedness saw service in heavy-haul environments similar to those served by Southern Railway (U.S.) coal drags and in mixed-freight service on corridors once controlled by Chicago and North Western Transportation Company.

Preservation and Legacy

Many GP40s survive in preservation, tourist, and shortline service with organizations such as the Narrow Gauge Railroad preservation societies, historical museums resembling collections at the Illinois Railway Museum, and private owners who maintain operational examples for excursion use. The GP40’s influence is evident in subsequent EMD designs and in extensive rebuild programs executed by industry players including GATX Corporation leasing fleets and shop groups at Norfolk Southern Railway heritage facilities. Its design legacy persists in modern diesel-electric practice and in the rosters of regional carriers descended from Class I predecessors like Burlington Northern Railroad and Southern Pacific Transportation Company.

Category:Diesel-electric locomotives