GP40

GP40
Name	GP40
Powertype	Diesel-electric
Builder	Electro-Motive Division
Builddate	1965–1971
Totalproduction	1,225
Wheelarrangement	B-B (AAR)
Primemover	EMD 645 V16
Poweroutput	3,000 hp (2,237 kW)
Tractiveeffort	61,000 lbf (starting)
Fuelcap	2,400 US gal
Disposition	Many rebuilt, preserved, or scrapped

GP40 is a four-axle diesel-electric road-switcher locomotive built by Electro-Motive Division for Class I and regional railroads across United States and Canada during the late 1960s and early 1970s. Combining the EMD 645 prime mover with a rugged frame and flexible multiple-unit capability, it became a workhorse for freight, manifest, and local services on networks such as Pennsylvania Railroad, Atchison, Topeka and Santa Fe Railway, and Southern Pacific. The GP40 influenced subsequent models like the GP40-2 and saw widespread adoption, rebuilding programs, and preservation by museums including the Illinois Railway Museum.

Design and Development

EMD designed the GP40 as part of a lineage including the GP35 and GP38 to meet growing horsepower demands from carriers such as Union Pacific Railroad and Norfolk and Western Railway. The locomotive used the EMD 645 V16 two-stroke diesel derived from previous EMD 567 work, coupled to an EMD D50 series generator and EMD axle-mounted traction motors similar to those used on contemporaries like SD40. EMD engineers emphasized modular maintenance practices favored by railroads including Penn Central and Conrail, and incorporated features requested by railroads such as dynamic braking systems for mountainous routes like those served by Southern Railway subsidiaries. The GP40's carbody, radiator layout, and electrical cubicle layout reflected lessons from operations on transcontinental routes like the Transcontinental Railroad corridors.

Technical Specifications

The GP40 employed a 16-cylinder EMD 645E3 producing 3,000 horsepower at 900 rpm, driving an EMD main generator to power four EMD traction motor assemblies in a B-B wheel arrangement. The locomotive's starting tractive effort and continuous tractive effort figures met requirements set by heavy-haul operators including Canadian National Railway and Canadian Pacific Railway. Fuel capacity, electrical control systems, and braking components made it suitable for interchange service between carriers such as Chessie System and Seaboard Coast Line Railroad. Cooling systems and radiator sectioning reflected adaptations for climates from Pacific Northwest mountain passes to Southeast United States flatlands. The GP40 could be equipped with dynamic brakes, multiple-unit control compatible with AAR standards, and optional steam generators for passenger conversions requested by carriers like Amtrak during early fleet transitions.

Production and Variants

EMD produced 1,225 GP40s from 1965 to 1971, delivered to a diverse roster including Illinois Central, Burlington Northern, and Missouri Pacific Railroad. Variants and derivatives included the later GP40-2 with updated electronics, and special builds for commuter agencies and shortlines like Metra affiliates. Export and modified versions served international operators such as Ferrocarriles Nacionales de México and industrial operators in the Oil Patch regions, often fitted with larger fuel tanks or sand capacity at the request of purchasers like CSX Transportation predecessor lines. Some units featured high short hoods, low noses, or extended-range tanks specified by regional buyers including Southern Pacific and Denver and Rio Grande Western Railroad.

Operational History

Railroads deployed GP40s across freight rosters for manifest, local, and secondary mainline service on corridors operated by Pennsylvania Railroad successors, Chicago and North Western Railway, and Great Northern Railway successors. The model proved versatile in roster consolidation events following mergers such as Conrail formation and the creation of Burlington Northern Santa Fe Railway. GP40s ran across major yards and terminals including Alton, Chicago Union Station approaches, and transcontinental routes serving the Port of Los Angeles complex. Operators used GP40s in road-switching, hump yard service, and helper assignments in mountainous districts like those controlled by Southern Pacific until higher-adhesion six-axle models replaced some units on heavy tonnage assignments.

Modifications and Rebuilds

Starting in the 1980s, numerous GP40s underwent extensive rebuild programs by shops associated with Electro-Motive Diesel successors and railroad-owned facilities such as Monongahela Railway shops and Paducah shops. Rebuilds produced GP40 variants with updated electronics, microprocessor controls, and emissions-related modifications requested by agencies including Environmental Protection Agency-driven programs. Notable rebuilds include conversions to the GP40-2 specification, installations of HT-C trucks in some fleets, and cab upgrades for safety standards influenced by Federal Railroad Administration rulemaking. Shortline operators and industrial users retrofitted units with dynamic braking changes, new traction motors, or repowered with later-model prime movers for improved fuel efficiency for customers like Providence and Worcester Railroad.

Preservation and Museum Units

Several GP40s have been preserved and restored by museums and tourist railroads including the Illinois Railway Museum, California State Railroad Museum, and the National Railroad Museum. Preserved examples often display original railroad liveries from lines such as Atchison, Topeka and Santa Fe Railway and Seaboard System Railroad, while others reflect rebuilt and modernized appearances from Conrail or CSX service. Tourist operations have used preserved GP40s on excursion lines linked to heritage events like Railfair and anniversary celebrations hosted by regional historical societies including the Railroad Museum of Pennsylvania. Preservationists continue restoration work to maintain operational examples for education, film, and special-event use along corridor segments formerly served by operators like Norfolk Southern Railway.

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