EMD SD7

The SD7 was conceived as a modification of the existing EMD GP7 with two additional powered axles, one for each truck. Providing two more axles served two purposes: it gave the locomotive more tractive effort compared to the four-axle GP7, and it distributed the locomotive's weight more evenly. EMD produced its first examples of the SD7 in May 1951, using the 567B engine. Starting in August 1953 a total of 26 SD7s were produced which used either the 567BC engine or the 567C engine. SD7s were originally set up to run long hood forward, usually noted by the letter "F" painted adjacent to the top step of the long hood boarding steps. Many were later changed or upgraded to run short hood forward as is today's Association of American Railroads standard. EMD ended production in November 1953 and began producing the SD7's successor, the SD9, in January 1954. == Rebuilds ==

SD7R The Southern Pacific Transportation Company (SP) had rebuilt a total of 42 of their SD7 locomotives into the EMD SD7R. They were numbered 1500–1542. The rebuilds had also included upgrades to the electrical systems, traction motors, as well as a changeout of the prime movers swapping the 16-cylinder 567B prime movers with 16-cylinder 645CE prime movers. The Chicago and North Western Transportation Company (C&NW) had seven SD7s rebuilt at their own Oelwein shops in Oelwein, Iowa changing their power output from 1,500 horsepower (1.12 Megawatts) to 1,750 horsepower (1.30 Megawatts). All seven C&NW units were retired from the C&NW's roster on September 5, 1986, and sold to the Dakota, Minnesota and Eastern Railroad (DM&E). == Original buyers ==

Currently preserved • Burlington Northern #6008 (ex-Great Northern #558) is preserved at the Minnesota Transportation Museum in Saint Paul, Minnesota. #6008 was one of the first 20 SD7s to be built in 1952; it's currently under restoration to its original appearance as Great Northern #558. • Southern #197 is preserved at the Virginia Museum of Transportation. It was originally built as Central of Georgia #201. • Southern Pacific #1518 (ex-EMD demonstrator #990), is preserved in operational condition at the Illinois Railway Museum. #1518 was the first SD7 (later converted into an SD7R) built by EMD. • The Dakota Southern Railway rosters one SD7, #512 (ex-MILW #2212) • ILSX #1751 (ex-Pennsylvania Railroad #8589) is in operation at Red Trail Energy in Richardton, ND. • Nevada Northern Railway 401 is in service at the Intermountain Power Plant in Delta, Utah. When retired, it will be donated to the Nevada Northern Railway Museum, as part of an agreement with the museum. == References ==