An EMD SD40X is an 6-axle diesel locomotive

Locomotive

A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...

 built by General Motors Electro-Motive Division between 1964 and 1965. 9 examples of this locomotive were built for test purposes to test the new 645-series

EMD 645

The EMD 645 family of diesel engines was designed and manufactured by the Electro-Motive Division of General Motors. Intended primarily for locomotive, marine and stationary engine use, one 16-cylinder version powered the 33-19 "Titan" prototype haul truck designed by GM's Terex...

 prime mover. After testing, eight were sold to the Union Pacific Railroad

Union Pacific Railroad

The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....

 and one example to the Gulf, Mobile and Ohio Railroad

Gulf, Mobile and Ohio Railroad

The Gulf, Mobile and Ohio was a Class I railroad in the central United States whose primary routes extended from Mobile, Alabama, and New Orleans, Louisiana, to St...

. This locomotive is an experimental testbed for the production SD40

EMD SD40

The EMD SD40 is a 6-axle diesel locomotive built by General Motors Electro-Motive Division between January 1966 and August 1972.-Design:Like its predecessor in EMD's catalog, the SD35, the SD40 is a high-horsepower, six-motor freight locomotive....

, but built on the shorter SD35

EMD SD35

An EMD SD35 is a 6-axle diesel locomotive built by General Motors Electro-Motive Division between June 1964 and January 1966. Power was provided by an EMD 567D3A 16-cylinder engine which generated . A fuel tank was used on this unit. This locomotive model shared a common frame with the EMD SD28,...

 frame. This locomotive was also known as an SD35X.

The designation SD40X was also given to an experimental version of the SD50

EMD SD50

The EMD SD50 was a diesel-electric locomotive built by General Motors Electro-Motive Division. It was introduced in May 1981 as part of EMD's "50 Series", but prototype SD50S locomotives were built from 1980; production ceased in January 1986...

, built by EMD on an SD40-2

EMD SD40-2

The EMD SD40-2 is a C-C locomotive produced by EMD from 1972 to 1989.The SD40-2 was first introduced in January 1972 as the mid-range offering in EMD's six-axle "Dash-2" series, competing against the GE U30C and the MLW M630...

 frame. 4 examples of this SD40X were built in 1979 and were delivered to the Kansas City Southern

Kansas City Southern Railway

The Kansas City Southern Railway , owned by Kansas City Southern Industries, is the smallest and second-oldest Class I railroad company still in operation. KCS was founded in 1887 and is currently operating in a region consisting of ten central U.S. states...

as KCS 700-703.

External links

• Thompson, J. David. EMD SD35, SD40X (Prototypes) and related models Original Owners