EMD GP40

EMD GP40. The EMD GP40 is a four-axle, 3,000 horsepower diesel-electric locomotive manufactured by the General Motors Electro-Motive Division between 1965 and 1971. As part of EMD's successful GP series, it was designed as a higher-horsepower successor to models like the EMD GP35 and became a dominant road switcher during the late 1960s railroad industry. Its introduction coincided with a period of significant mergers and acquisitions in North American railroading, and it served as a primary freight power for numerous Class I railroads, including the Southern Pacific, the Santa Fe, and the Penn Central.

Development and production

The development of this locomotive was driven by the competitive pressures of the dieselization era and the need for more powerful single-engine units. Engineers at the Electro-Motive Division leveraged advancements from the EMD 645 engine series to achieve the 3,000 horsepower benchmark. Production commenced at EMD's primary facility in La Grange, Illinois in November 1965, following the successful market reception of the lower-powered EMD GP35. Key early purchasers included the Seaboard Air Line Railroad and the Louisville and Nashville Railroad, which placed substantial orders. In total, 1,221 units were constructed before production ended in December 1971, making it one of the best-selling models in its horsepower class during that period.

Design and specifications

The locomotive utilized a standardized carbody design common to EMD's GP series, featuring a high short hood and a central cab. Its prime mover was a 16-cylinder, turbocharged EMD 645E3 diesel engine, which directly drove a main DC generator. This generator provided power to four DC traction motors, one mounted on each axle in a B-B wheel arrangement. Standard features included a modular electrical cabinet, often referred to as the "36-seat" layout by railroad crews, and an improved dynamic braking system compared to earlier models. The unit was designed for versatility, capable of both heavy road freight and switching duties, with a typical starting tractive effort exceeding 65,000 pounds-force.

Service history

Upon delivery, these locomotives were immediately deployed into mainline freight service across the United States and Canada. They were workhorses for railroads undergoing consolidation, such as the newly formed Penn Central and the later Burlington Northern Railroad. Many units saw decades of service, hauling everything from unit coal trains on the Norfolk and Western Railway to intermodal traffic on the Southern Railway (U.S.). Their reliability led to extensive rebuilding programs in the 1980s and 1990s by railroads like the CSX and the Union Pacific Railroad, which often upgraded them with modern electronics and re-designated them under new model classifications.

Variants and derivatives

Several notable variants were produced based on this core design. The EMD GP40-2, introduced in 1972, featured an improved electrical system and became even more prolific. For passenger service, EMD produced the EMD FP40, which included a steam generator for heating passenger cars. The EMD SD40 shared the same prime mover but utilized a six-axle C-C wheel arrangement for higher adhesion. Furthermore, many original units were later rebuilt by their owners into models like the GP40-3 or GP40-2L, often for regional carriers such as the Wisconsin Central Ltd..

Preservation

Numerous units have been preserved in operational or static display condition by historical organizations and museums. Examples include units originally owned by the Santa Fe Railway on display at the California State Railroad Museum in Sacramento. The Railroad Museum of Pennsylvania in Strasburg also holds a former Pennsylvania Railroad-painted unit. Several preserved locomotives remain in operation on tourist and excursion lines, such as those run by the Durango and Silverton Narrow Gauge Railroad and various regional heritage railroads across the Midwestern United States.

Category:Diesel locomotives Category:General Motors locomotives Category:1965 introductions