TheEMD SD9 is a model ofdiesel locomotive built byGeneral Motors Electro-Motive Division between January 1954 and June 1959. AnEMD 567C 16-cylinder engine generated 1,750 horsepower (1.30 MW). Externally similar to its predecessor, theSD7, the SD9 was built with the improved and much more maintainable 567C engine.[2]
471 SD9s were built forAmerican railroads, while a further 44 were produced for export.[2]
Many SD9s both high and short hood can still be found in service today on shortline railroads and industrial operators.[3] Although most Class 1 roads stopped using these locomotives by the 1970s and 1980s, some remain in rebuilt form on some majorClass I railroads, as switcher locomotives.[4]
The SD9 was the second model of EMD's SD (special duty) line of locomotives, following the SD7. Just as the SD7 was a lengthenedGP7 with two additional axles, the SD9 was a corresponding modification of theGP9. 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.[5]
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.[6]
The last phase of construction had a carbody similar to theSD18 andSD24, and used two 48-inch (1,219 mm) cooling fans instead of four 36-inch (914 mm) cooling fans.
EMD ended SD9 production in June 1959. It was succeeded by theSD18 which began production in 1960.
EMD produced a lightweight variant of the SD9, named theSD9s. This locomotive had its weight reduced for service on lighter tracks with modifications such as a smaller fuel tank.[6]
TheSD9m was a rebuild fromSD7s and SD9s mostly byNorfolk Southern Railway. NS rebuilt a total of ten units and used them in service between 1989 and 2010.
Between August 1970 and March 1980, theSouthern Pacific Transportation Company had rebuilt 144 of their units into EMD SD9E locomotives under their own rebuild program known as the General Rehabilitation and Improvement Program (G.R.I.P). 142 of their rebuilt units were renumbered as 4300-4441 and two additional rebuilt units being renumbered as 4450 and 4451. These 142 units were also reclassified as EF618E-1, with their two units #4450 and #4451 as EF618E-2, which had left six other SD9 locomotives un-rebuilt.[7][8]
BNSF #6125 (ex-GN #598) is preserved at the Inland Northwest Rail Museum atReardan, Washington, having been donated in 2020. It is being restored into its originalGreat Northern appearance.
Great Northern #599 is preserved by the Inland Northwest Rail Museum inReardan, Washington. It will undergo a cosmetic restoration, with mechanical parts used for the restoration of #598.[11]
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 byNorfolk Southern.
Southern Pacific #5399 is preserved on theAlbany & Eastern Railroad (AERC). Restored to SP's "Black Widow" paint scheme, it is used for both freight and passenger service.
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.[9]
^Schafer, Mike (1998).Vintage diesel locomotives. Osceola, WI: Motorbooks International. pp. 36–37.ISBN0-7603-0507-2.OCLC38738930.
^abMarre, Louis A. (1995).Diesel locomotives : the first 50 years : a guide to diesels built before 1972. Waukesha, WI: Kalmbach Pub. Co. pp. 66–67.ISBN0-89024-258-5.OCLC34531120.
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