| EMD SD7 | |
| Powertype: | Diesel-electric |
| Builder: | General Motors Electro-Motive Division (EMD) |
| Buildmodel: | SD7 |
| Builddate: | May 1951 - November 1953 |
| Totalproduction: | 188 |
| Aarwheels: | C-C |
| Trucks: | EMD Flexicoil C |
| Wheeldiameter: | 400NaN0 |
| Minimumcurve: | 23° (2502NaN2 radius) |
| Wheelbase: | 48feet |
| Length: | 61feet |
| Width: | 10feet |
| Height: | 15feet |
| Locoweight: | 309000lb |
| Fuelcap: | 1200usgal |
| Primemover: | EMD 16-567B |
| Rpmrange: | 800 |
| Enginetype: | V16 diesel engine |
| Aspiration: | Roots-type supercharger |
| Displacement: | 9072cuin |
| Generator: | D-12-C |
| Tractionmotors: | (6) D-27-B |
| Cylindercount: | 16 |
| Poweroutput: | 15002NaN2 |
| Tractiveeffort: | 77250lbf |
| Locale: | United States |
| Disposition: | Some still in service, others preserved |
The EMD SD7 is a model of 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 1500hp for its six traction motors. United States railroads bought 188 units.[1]
This was the first model in EMD's SD (Special Duty) series of locomotives, a lengthened B-B GP7 with a C-C truck arrangement. The two extra axles and traction motors are useful in heavy, low-speed freight service. EMD continues to produce SD series locomotives to this day. Some SD7s both high and short-hood can still be found in service today on shortline railroads and industrial operators, although most Class I roads stopped using these locomotives by the 1970s and 1980s.[2] [3]
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.[4]
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.
The Southern Pacific Transportation Company had rebuilt a total of 42 of their SD7 locomotives into the EMD SD7R.
| Image | Owner | Quantity | Numbers | Notes | Ref. | |
|---|---|---|---|---|---|---|
| 2 | 990 | to Southern Pacific 5308 then 2715 to 1415 ne 1518 | [5] | |||
| 991 | to Baltimore and Ohio 760 | |||||
| 4 | 761–764 | These units were built with the 567BC engine. | ||||
| 8 | 451–455, 801–803 | |||||
| 5 | 1660–1664 | |||||
| 37 | 300–324, 400–411 | 322-324 were built with the 567BC engine. To Burlington Northern 6023-6059 | ||||
| Chicago, Burlington and Quincy Railroad (Colorado and Southern Railway) | 10 | 810–819 | To Burlington Northern 6070-6079 | |||
| Chicago, Burlington and Quincy Railroad (Fort Worth and Denver Railway) | 11 | 850–860 | 858-860 were built with the 567BC engine. To Burlington Northern 6080-6090 | |||
| 24 | 2200–2223 | Renumbered 500–523, 2215-2223 were built with the 567BC engine. | ||||
| 1 | 201 | |||||
| 5 | 5300–5304 | |||||
| 23 | 550–572 | To Burlington Northern 6000-6022 | [6] | |||
| 1 | 903 | |||||
| 2 | 852, 952 | Renumbered 300–301. To Chicago and North Western Railway. | ||||
| 1 | 401 | Sold to LADWP in the 1980s; reacquired by Nevada Northern in 2021, along with RSD-4 #201. | [7] | |||
| 2 | 8588–8589 | These units were built with the 567BC engine | ||||
| 42 | 5279–5293, 5309–5335 | 5321-5323, 5334-5335 were built with the 567C engine | ||||
| 10 | 775–784 | |||||
| Total | 188 |