EMD GP40-2

The EMD GP40-2 entered production in April 1972 as part of Electro-Motive Division's revised Dash 2 series, which represented a comprehensive updating of EMD's road switcher line through improved electrical components, modular electronics, and enhanced reliability features. The Dash 2 designation signaled a significant refinement rather than a wholesale redesign, and the GP40-2 carried forward the basic four-axle, 3,000-horsepower formula of its predecessor, the GP40, while incorporating the lessons learned from years of field experience. American railroads operating in an era of increasing freight demands found the locomotive an attractive option for mainline service, and domestic production for United States carriers reached 817 units over the course of the model's run. Canadian production added a substantial further contribution to the total, as General Motors Diesel built 279 examples of the type at its London, Ontario facility between 1974 and 1976. Mexican railroads also received 44 units of the standard variant, reflecting the locomotive's appeal across North American carriers of varying size and operating environment. A small passenger-oriented variant, the GP40P-2, was produced in a run of just three units in 1974, equipped for head-end power requirements. When all variants are combined, total production across the model's fourteen-year run from 1972 to 1986 reached 1,143 units. The GP40-2's legacy extended well beyond its original delivery years, as several major railroads undertook substantial rebuild programs to extend the useful lives of their fleets. Union Pacific transformed 129 of its GP40 and GP40-2 units into GP40N locomotives at its Jenks Shop, fitting them with microprocessor control systems to improve adhesion characteristics and modernize the control architecture. CSX similarly rebuilt a portion of its GP40-2 fleet into GP40-3 variants featuring new cabs and updated electronics, while one unit was later converted into an experimental hydrogen fuel cell locomotive in a collaborative project with CPKC, demonstrating the durability and adaptability of the basic platform decades after original construction.

The GP40-2 is powered by the EMD 645E3, a 16-cylinder turbocharged version of EMD's 645-cubic-inch-per-cylinder two-stroke prime mover, producing 3,000 horsepower. The locomotive rides on a B-B wheel arrangement, meaning two two-axle powered trucks, with all four axles driven by DC traction motors. With standard 62:15 gearing, EMD rated the locomotive's continuous tractive effort at 55,400 pounds, with a maximum speed in the range of 65 to 70 miles per hour depending on final drive configuration. The Dash 2 electrical system introduced modular components that simplified field maintenance by allowing technicians to swap out individual circuit boards rather than troubleshoot complex wiring harnesses, a practical improvement that contributed meaningfully to availability and reduced downtime for operators. Some units were equipped with the PF21 wheel slip module, which limited power output below approximately 23 miles per hour and brought the continuous speed threshold down to around 11 miles per hour, improving adhesion in low-speed, high-drawbar-load conditions common during heavy freight assignments. The overall platform was compact enough to serve in branch or secondary line applications while remaining capable on mainline assignments, which contributed to its widespread adoption across a diverse range of North American railroads throughout the 1970s and into the 1980s.

Models by: Athearn · Atlas