An EMD SD7 is a 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 February 1952 and November 1953. Power was provided by an EMD 567B 16-cylinder

Cylinder (engine)

A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

 engine which generated 1500 hp.

188 examples of this locomotive model were built for American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 railroads.

This was the first model in EMD's SD (Special Duty) series of locomotives, later models of which are still being produced.

Original buyers

Owner	Quantity	Numbers	Notes
Electro-Motive Division	2	990	to Southern Pacific 5308
		991	to Baltimore and Ohio 760
Baltimore and Ohio Railroad Baltimore and Ohio Railroad The Baltimore and Ohio Railroad was one of the oldest railroads in the United States and the first common carrier railroad. It came into being mostly because the city of Baltimore wanted to compete with the newly constructed Erie Canal and another canal being proposed by Pennsylvania, which...	4	761–764
Bessemer and Lake Erie Railroad Bessemer and Lake Erie Railroad The Bessemer and Lake Erie Railroad is a class II railroad that operates in northwestern Pennsylvania and northeastern Ohio.The railroad's main route runs from the Lake Erie port of Conneaut, Ohio to the Pittsburgh suburb of Penn Hills, Pennsylvania, a distance of 139 miles...	8	451–455, 801–803
Chicago and North Western Railway Chicago and North Western Railway The Chicago and North Western Transportation Company was a Class I railroad in the Midwest United States. It was also known as the North Western. The railroad operated more than of track as of the turn of the 20th century, and over of track in seven states before retrenchment in the late 1970s...	5	1660–1664
Chicago, Burlington and Quincy Railroad Chicago, Burlington and Quincy Railroad The Chicago, Burlington and Quincy Railroad was a railroad that operated in the Midwestern United States. Commonly referred to as the Burlington or as the Q, the Burlington Route served a large area, including extensive trackage in the states of Colorado, Illinois, Iowa, Kentucky, Missouri,...	37	300–324, 400–411
Chicago, Milwaukee, St. Paul and Pacific Railroad Chicago, Milwaukee, St. Paul and Pacific Railroad The Milwaukee Road, officially the Chicago, Milwaukee, St. Paul and Pacific Railroad , was a Class I railroad that operated in the Midwest and Northwest of the United States from 1847 until its merger into the Soo Line Railroad on January 1, 1986. The company went through several official names...	24	2200–2223	Renumbered 500–523
Colorado and Southern Railway Colorado and Southern Railway The Colorado and Southern Railway was a railroad company in the western United States that operated independently from 1898 to 1908, then as part of the Chicago, Burlington and Quincy Railroad until it was absorbed into the Burlington Northern Railroad in 1981.The railway began as the...	10	810–819
Central of Georgia Railway	1	201
Denver and Rio Grande Western Railroad Denver and Rio Grande Western Railroad The Denver & Rio Grande Western Railroad , often shortened to Rio Grande or D&RGW, formerly the Denver & Rio Grande Railroad, is a defunct U.S. railroad company. The railroad started as a narrow gauge line running south from Denver, Colorado in 1870; however, served mainly as a transcontinental...	5	5300–5304
Fort Worth and Denver Railway Fort Worth and Denver Railway The Fort Worth and Denver Railway , nicknamed "the Denver Road," was a class I American railroad company that operated in the northern part of Texas from 1881 to 1982, and had a profound influence on the early settlement and economic development of the region....	11	850–860
Great Northern Railway	23	560–572
Kennecott Copper Corporation	1	903
Minneapolis and St. Louis Railway Minneapolis and St. Louis Railway The Minneapolis and St. Louis Railway was an American Class I railroad that built and operated lines radiating south and west from Minneapolis, Minnesota which existed for 90 years from 1870 to 1960....	2	852, 952	Renumbered 300–301
Nevada Northern Railway Nevada Northern Railway The Nevada Northern Railway was a railroad in the U.S. state of Nevada, built primarily to provide rail access to a major copper producing area in White Pine County, Nevada...	1	401
Pennsylvania Railroad Pennsylvania Railroad The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....	2	8588–8589
Southern Pacific Company	42	5279–5293, 5309–5335
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....	10	775–784
Total	188

Preservation

The first SD7 built by EMD, former demonstrator 990, Southern Pacific 1518

Southern Pacific 1518

Southern Pacific Railroad's number 1518 is an EMD SD7 diesel locomotive. It was built originally in May 1951 as General Motors Electro-Motive Division's Demonstrator #990. It was the first "SD" series locomotive ever built. Its road number 990 is in reference to its EMD Engineering Department...

, is preserved in operational condition at the Illinois Railway Museum

Illinois Railway Museum

The Illinois Railway Museum is the largest railroad museum in the United States and is located in Union, Illinois, northwest of Chicago...

.