 The engine is rated at .The 645 series, introduced in 1966, was EMD’s standard engine through the 1980s.In the early 1970s railroads were starting to convert to AC power, the six largest buyers, Milwaukee (64), Southern Pacific (58), Seaboard Coast Line Railroad (45), Nacionales de México (25), Long Island (23), and Louisville & Nashville (10), were all buying AC road locomotives.