The EMD SD40 is a model of 6-axle diesel-electric locomotive built by General Motors Electro-Motive Division between January 1966 and August 1972. 1,268 locomotives were built between 1966 and 1972. In 1972, an improved version with new electronics was developed and marketed as a new locomotive, the SD40-2.
Like its predecessor in EMD's catalog, the SD35, the SD40 is a high-horsepower, six-axle freight locomotive. The SD40 is a member of EMD's long-running <u>S</u>pecial <u>D</u>uty class of locomotives, which all are built with 6 axles.
In 1966, EMD updated its locomotive catalog with entirely new models, all powered by the new 645 diesel engine. These included six-axle models SD38, SD40, SDP40 and SD45. All shared standardized components, including the frame, cab, generator, trucks, traction motors, and air brakes. The primary difference was the power output: SD38 = from a non-turbocharged V16, SD40 = from a turbocharged V16, and SD45 = from a turbocharged V20.
856 examples of this locomotive model were built for American railroads, 330 were built for Canadian railroads, 72 were built for Mexican railroads, 6 were built for the Guinea-Boke Project, and 4 SD40Ms riding on gauge trucks were exported to Brazil. They were manufactured at McCook, Illinois.
Built by GMD at London, Ontario
Export SD40's Built by EMD at McCook, Illinois or GMD at London, Ontario
Phases are as listed by Robert Sarberenyi.
The very first test bed SD40, EMD 434, constructed on an SD35 frame in July 1964 was in active service until retired by Canadian National Railway in March 2009 and donated to the Monticello Railway Museum in July 2009, albeit having been upgraded to an "SD40-2R", as Illinois Central 6071.
18 customized SD40s were built for the Illinois Central Railroad as model SD40A, using the longer SDP45 frame, which allowed for a larger 5,000 gallon fuel tank.
Versions of the SD40 modified for the Australian loading gauge were sold to WAGR and Victorian Railways as their L and C classes respectively.
The SD40 was succeeded by an upgraded Dash 2 version called the SD40-2.
After having been succeeded by the more modern SD40-2, a large number of SD40s have been upgraded with more modern equipment. The main difference between rebuilt SD40s and genuine SD40-2s is that the latter use a longer frame and have longer front and rear porches, while the rebuilt SD40s have a shorter frame.
A common product of rebuilding SD40s, and sometimes SD40-2s, is an SD40-3. The major addition denotes that the rebuilt unit or units as an SD40-3 is the addition of a micro-processor, and sometimes other modern components. The usual reasons for installing a micro-processor are improved traction control, and better fuel economy (via better injection control). Also, electronic control over braking systems (independent and automatic). This may include some SD39, SD45 and SD45-2 rebuilt to SD40-2 standards.
The SD40R is a rebuilt of all the Southern Pacific's SD40 between 1980 and 1981.
The SD40M-2 was a rebuild done by Morrison Knudsen for two railroads, the Southern Pacific, using 97 SD45s, 30 SD40s and 6 SDP45s, and the Canadian Pacific, using another three SD40s and seven SD45s.
The SD40-2XR designates 15 SD40 and a SDP40 rebuilt to Dash-2 standards for Montana Rail Link.
The SD40E is an SD50 rebuilt by the Norfolk Southern Railway and derated to 3000 HP (equivalent to an SD40-2).