McIntosh & Seymour 538

The McIntosh & Seymour 538 was a six-cylinder diesel prime mover built at Auburn, New York for locomotives of the American Locomotive Company (Alco). It replaced the 531 with a similar output and upgraded components, entered production in 1938, and came in a naturally aspirated form of 660 horsepower and, as the 538T, a turbocharged form of 1,000 horsepower. It powered the later HH600 switchers, the HH660 switchers built from October 1938 to April 1940, and the HH1000, which replaced the HH900 in 1939; a few HH900 units also received the 538T. Its cylinders had the same dimensions as those of the 539, the engine that was developed from it by lowering the engine base into the frame so that the locomotive hood could be lower.