The EMD SD89MAC is a 4,500 horsepower (3,360 kW) C-Cdiesel-electric locomotive produced by General Motors Electro-Motive Division. Along with the SD80MAC and SD90MAC, the SD89MAC is one of the largest single-engine locomotives produced by EMD, surpassed only by the dual-engined DD series. The SD89MAC features radial steering trucks and an isolated cab which is mounted on shock absorbers to reduce vibration. The SD89MAC uses AC traction motor technology. Like the SD90MAC, it is a hood unit fitted with a safety cab and has an enlarged radiator section, nearly the entire width of the locomotive, which makes it easy to spot. Currently EMD has used EMD SD89MAC 92 for Tier 4 Experiments.