EMD GP39-2

The EMD GP39-2 was introduced in 1974 as part of Electro-Motive Division's broader Dash 2 series, which represented a significant refinement of the builder's earlier locomotive designs through improved electrical systems, modular components, and enhanced reliability. The GP39-2 was essentially an upgraded successor to the GP39, a model that had struggled commercially against the naturally aspirated GP38, which railroads had favored for its proven dependability. The GP39-2 managed to carve out a more respectable market position than its predecessor, with 249 units ultimately constructed over a production run that stretched from 1974 through 1984. The improved commercial reception of the GP39-2 relative to the original GP39 owed much to the economic circumstances of the 1970s. The energy crisis of that decade made fuel efficiency a considerably higher priority for railroad purchasing departments, and the GP39-2's turbocharged prime mover offered better fuel economy compared to the more powerful GP38-2 under certain operating conditions. The locomotive also demonstrated stronger performance at higher elevations, making it attractive for operations in mountainous territory. Purchasers included several American Class I railroads as well as at least one industrial operator, Kennecott Utah Copper, which employed the type in its mining operations. The legacy of the GP39-2 has extended beyond its original service lives through rebuild programs. Union Pacific, one of the model's operators, undertook a program at its Jenks Shop facility to convert a number of its GP39-2 units into GP39N locomotives, equipping the rebuilt machines with microprocessor control systems to improve adhesion characteristics and extend their operational usefulness. One example, a former Reading Company unit numbered 3412, survived into preservation at the Reading Railroad Heritage Museum in Hamburg, Pennsylvania, representing the class in static display.

The GP39-2 was powered by a turbocharged 12-cylinder version of EMD's 645E3 diesel engine, producing 2,300 horsepower and setting it apart from the non-turbocharged 16-cylinder 645E engine used in the GP38-2, which generated 2,000 horsepower. The use of a turbocharger allowed EMD to extract greater power from fewer cylinders, contributing to the fuel efficiency advantage the GP39-2 held under certain load conditions. The locomotive rode on a B-B wheel arrangement, meaning two two-axle powered trucks, and employed direct current traction motors, consistent with the broader EMD practice of the era before the widespread adoption of alternating current drive systems. As a member of the Dash 2 family, the GP39-2 incorporated the modular electrical cabinet design that was a hallmark of the series, intended to simplify maintenance and reduce locomotive downtime by allowing easier component replacement in the field. The overall carbody and underframe followed the general-purpose road switcher configuration that had defined the GP line since the 1950s, providing crews with good visibility and flexibility for both road and switching assignments. At approximately 2,300 horsepower, the GP39-2 occupied a middle tier in EMD's four-axle lineup, offering more power than the GP38-2 while falling below the output of the six-axle and higher-horsepower models in the Dash 2 range.

Models by: Athearn · Atlas