EMD SD9

The SD9 was the second model of EMD's SD (special duty) line of locomotives, following the SD7. Just as the SD7 was a lengthened GP7 with two additional axles, the SD9 was a corresponding modification of the GP9. The additional axles in SD series locomotives provide more tractive effort and more even distribution of locomotive weight compared to the four axle GP series locomotives. SD9s can be distinguished from the similar looking SD7s by observing the position of the classification lights on the ends of the locomotive, above the number board. The SD9's classification lights are on a small pod, canted outward, while the SD7's classification lights are closer to the centerline and flush with the hood. The last phase of construction had a carbody similar to the SD18 and SD24, and used two cooling fans instead of four cooling fans. EMD ended SD9 production in June 1959. It was succeeded by the SD18 which began production in 1960. == Variants ==

SD9s EMD produced a lightweight variant of the SD9, named the SD9s. This locomotive had its weight reduced for service on lighter tracks with modifications such as a smaller fuel tank. == Original buyers ==

Some SD9 locomotives can be found in museums and on tourist lines, and at least two are in service on a working railroad. • BNSF #1550 is preserved at the Lake Superior Railroad Museum, having been donated by BNSF in 2022. It is classified as an SD9-3. • BNSF #6125 (ex-GN #598) is preserved at the Inland Northwest Rail Museum at Reardan, Washington, having been donated in 2020. It is being restored into its original Great Northern appearance. Sister locomotive Great Northern #599 is also preserved by the same museum and will undergo a cosmetic restoration, with mechanical parts used for the restoration of #598. The 599 was previously donated to the city of Skykomish, WA and was on display until 2019-2022. Both were the only Great Northern SD9s built with dynamic brakes. • Burlington Northern #6139 is preserved and operational on the Oregon Coast Scenic Railroad. • Burlington Northern #6234 (ex-Colorado & Southern #839) is preserved and operational at the Minnesota Transportation Museum. It now operates on the museum's Osceola and St Croix Valley Railway. #6234 is an example of the last variation of SD9 locomotives produced, which used the SD18 carbody. • Korail 5025 is the only preserved SD9 in Korea, plinthed in front of , along single G12 4102. Both engines worked for construction of Korea Train Express Gyeongbu section as departmental vehicles after their retirement on Korail. • Milwaukee Road #532 is preserved and operational at the Whitewater Valley Railroad. • Nevada Northern Railway #204 (ex-SP #4426) is preserved and operational at the Nevada Northern Railway Museum in Ely, Nevada, and was recently repainted and renumbered to #250 to celebrate the United States Semiquincentennial in 2026. • Nickel Plate Road #358 is preserved and operational at the Fort Wayne Railroad Historical Society. It has been restored into its original appearance. • Norfolk and Western #2349 (ex-NKP #349) is preserved at the Mad River & Nickel Plate Railroad Museum. It was donated to the museum in December 2010 by Norfolk Southern. • Portland and Western Railroad #1854 is stored in Albany, Oregon. It was retired in February 2024. • Southern Pacific #4404 is preserved on the Pend Oreille Valley Railroad in Usk, Washington. • Southern Pacific #5399 is preserved on the Albany & Eastern Railroad (AERC). Restored to SP's "Black Widow" paint scheme, it is used for both freight and passenger service. • Southern Pacific #5472 is preserved and operational on the Niles Canyon Railway • Escanaba & Lake Superior Railroad #1221 and #1223 are operational on their shortline railroad. Unit #1221 is serving Michigan's Upper Peninsula and NE Wisconsin. Unit #1223 is assigned to Wells as backup switching power. Units #1222 and #1224 are stored OOS. Unit #1220 was OOS when purchased by ELS, stored for parts. Despite rumors, unit #1225 was never purchased by the ELS RR. ==References==