Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The EMD MP15AC is a 1,500 hp diesel switcher/road-switcher locomotive built by General Motors' Electro-Motive Division between August 1975 and August 1984. 246 examples were built, including 25 for export to Mexico, and four built in Canada. The MP15AC was a development of the earlier MP15DC model, but replaced the earlier model's DC generator with an alternator producing AC power which is converted to DC for the traction motors with a silicon rectifier. The MP15AC is 1.5 ft longer than an MP15DC, the extra space being needed for the rectifier equipment. The alternator-rectifier combination is more reliable than a generator, and this equipment became the standard for new diesel-electric locomotive designs.