The EMD SD38-2 is a model of six-axle diesel-electric locomotive built by General Motors Electro-Motive Division (EMD) from 1972 to 1979. EMD built 90 of these medium road-switchers, which were used in both yard and mainline roles. Part of the EMD Dash 2 line, the SD38-2 was an upgraded SD38 with modular electronic control systems, HT-C trucks, and many other detail improvements. The locomotive's power was provided by an EMD 16-645E 16-cylinder engine, which could generate 2,000 horsepower. These units were constructed with either 3,200 or 4,000 US gal fuel tanks and were available with or without dynamic brakes. It shared the same 64-foot-8-inch (19.71 m) frame as the SD40-2 and SD45-2, which gives it a length over couplers of 68 feet 10 inches (20.98 m).

The EMD 645 is a family of diesel engines that was designed and manufactured by the Electro-Motive Division of General Motors. While the 645 series was intended primarily for locomotive, marine and stationary engine use, one 16-cylinder version powered the 33-19 "Titan" prototype haul truck designed by GM's Terex division