Offering better reliability and lower maintenance costs than the higher powered SD-45, EMD’s SD40-2 enjoyed a long production run of 3,100 units. The 3,000 horsepower diesel was the primary motive power for many railroads throughout the 1970’s and 80’s. Introduced on January 1, 1972, the SD40-2 had become the best-selling 6-axle road switcher in history by December 31, 1978. One of the most striking features of the EMD workhorse was its long “back porch” or decking that extended in front and behind the locomotive’s cab. These porches differentiated the SD40-2 from its earlier cousin, the SD35 and were the result of the SD40-2’s requirement for a longer frame, which helped increase the locomotive’s tractive effort.