SD40/40-2

The Elctromotive Disvision SD40 is a 6 axle, 3,000 HP diesel-electric locomotive built from 1966 to 1972. The SD40 (along with the GP40, SD38, and GP38) introduced the new 16 cylinder 645 engine, replacing the old 567 engine found in the GP35, SD35 and all previous models. The SD40 did not sell as many units as it's sucessor, the SD40-2, largely due to the fact that it was offered simutainiously with the 20 cylinder, 3,600 HP SD45. At the time, railroads wanted a more powerful locomotive, and the SD45's 3,600 HP engine appealed more than the less powerful SD40.

The Electro Motive Division SD40-2 is a 6 axle, 3,000 HP diesel-electric locomotive built from 1972 until the early 1980's. It is generally considered the most sucessful diesel locomotive of all time, with over 4,000 units built. Though basically an SD40, the Dash 2 line saw a host of electrical upgrades, plus a longer frame on which the units road. The SD40-2 far outsold the Dash 2 version of the SD45, the SD45-2. Rising fuel prices in the 1970's made the more fuel efficient SD40-2 the locomotive of choice for most railroads.