The ALCO RSD-4 was a six axle

diesel-electric locomotive A diesel locomotive is a type of railway locomotive in which the prime mover (locomotive), prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conv ...

built by the

American Locomotive Company The American Locomotive Company (often shortened to ALCO, ALCo or Alco) was an American manufacturer of locomotives, diesel generators, steel, and tanks that operated from 1901 to 1969. The company was formed by the merger of seven smaller locomo ...

between 1951 and 1952. It was a derivative of the four-axle

ALCO RS-3 The ALCO RS-3 is a , B-B diesel-electric locomotive manufactured from May 1950 to August 1956 by American Locomotive Company (ALCO) and its subsidiary Montreal Locomotive Works (MLW). A total of 1,418 were produced: 1,265 for American railroads, ...

, with two additional powered axles which allowed better tractive effort at lower speeds. Due to the inadequate capacity of the main generator, this model was later superseded in production by the

ALCO RSD-5 The ALCO RSD-5 is a diesel-electric locomotive rated at , that rode on a pair of three-axle trucks, having a C-C wheel arrangement. Basically an upgraded version of the earlier ALCO RSD-4, and used in much the same manner as its four-axle cou ...

Original owners

Preserved units

The only ALCO RSD-4 that has survived is Kennecott Copper Corporation #201. It resided at the Northwest Railway Museum until November 2021 (formerly known as the Puget Sound & Snoqualmie Valley Railway) in

Snoqualmie, Washington Snoqualmie ( ) is a city next to Snoqualmie Falls in King County, Washington, United States. It is east of Seattle. Snoqualmie city is home to the Northwest Railway Museum. The population was 10,670 at the 2010 census and an estimated 13,62 ...

in its orange Kennecott paint scheme. As of 2021, it has been returned to Ely, Nevada (along with

EMD SD7 An SD7 is a 6-axle diesel locomotive built by General Motors Electro-Motive Division between May 1951 and November 1953. It had an EMD 567B 16-cylinder engine producing for its six traction motors. 188 were built for United States railroads. ...

#401) to the

Nevada Northern Railway Museum The Nevada Northern Railway Museum is a railroad museum and heritage railroad located in Ely, Nevada and operated by a historic foundation dedicated to the preservation of the Nevada Northern Railway. Museum activities include restoration and o ...

References

* * C-C locomotives RSD-04 Diesel-electric locomotives of the United States Railway locomotives introduced in 1951 Standard gauge locomotives of the United States {{diesel-loco-stub