(AZL SD40T-2) An EMD SD40T-2 is a 6-axle diesel locomotive. Power is provided by a 16- cylinder EMD 645E3 diesel engine capable of producing 3,000 horse-power. 312 examples of this locomotive were built for North American railroads between April 1974 and July 1980 . This locomotive, are called tunnel motors , because they were specifically designed to be more effective when operating in tunnels. The major differences are the radiator intakes and radiator fan grills located at the rear of the locomotive.