EMD SD39

The EMD SD39 is a 6-axle (C-C) diesel-electric locomotive built by General Motors Electro-Motive Division (EMD) between August 1968 and May 1970. Power was provided by an EMD 645E3 12-cylinder engine which generated 2,300 horsepower (1.7 MW). The SD39 was essentially a non-turbocharged version of the SD40, designed for railroads that preferred non-turbocharged engines due to maintenance concerns or operating conditions.

It was intended to provide a medium horsepower option in EMD's second generation of locomotives. The SD39 shared many components with other locomotives in the "Dash 2" line, although it predated that series by a few years. Its prime mover and electrical equipment were similar to other EMD locomotives of the period, making it relatively easy to maintain.

The SD39 found favor primarily with smaller railroads and those operating in mountainous regions where lower horsepower with high adhesion was desirable. The locomotive's relatively short production run and limited sales meant that it was not as widely adopted as its more powerful turbocharged cousins like the SD40 and SD45.