What began as a true "Special Duty" line of 6 axle locomotives has evolved into the standard power for nearly all of today's locomotive needs. EMD's SD series includes the best selling locomotive models of all time. From the mainline to museum collections and everything in between, the SD series remains a popular locomotive choice on railroads of all sizes, including model railroads.
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SD7 / SD9
The locomotive that started it all! The six-axle equivalent to the popular GP7 these locomotives were designed with branchlines and yard service in mind. The similar looking SD9 offered minor improvements
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The SD35 is easily distinguished by its small stature. With a hood much like the more common SD40, the SD35 uses the same frame as the SD7 - providing a smaller space for the fuel tank and very short end platforms.
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SD38Used in heavy haul work from iron ranges to hump yards, the SD38 was sold in low numbers but offered decades of reliable work.
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SD38-2With an updated electronics package, the SD38-2 offered similar performance and sales as the SD38.Continue to 5 of 20 below.
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SD39 / SD39-2
Even more rare than the SD38, the SD39 and SD39-2 offered a mid-sized locomotive option that few railroads found necessary.
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The SD40 was introduced as a mid range option which was overshadowed in early years by the larger SD45. Its reliability and efficiency quickly impressed buyers however and the SD40 would go on to be one of the most popular and long-lived EMD locomotive designs.
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SD40-2The best selling diesel of all time, the SD40-2 could be found on railroads all across North America.
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Adapted for life in the mountains, the SD40T-2 and SD45T-2 featured a revised radiator compartment which prevented overheating and stalls in the many tunnels along the Southern Pacific and Rio Grande mountain routes. Today these unique models can be found on railroads far removed from the mountain scenery.Continue to 9 of 20 below.
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The 3600 hp SD45 was the darling of EMD's 1964 catalog but was eclipsed in sales and reputation by the SD40. With its distinctive flared radiator, the SD45 maintained a devoted following of railroaders and fans and many still roam the rails - though most have been rebuilt to SD40-2 specs.
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Demand was strong enough for EMD to upgrade the SD45 to -2 standards in 1972. Although production was small compared to the SD40-2, the SD45-2 proved to have eliminated most of the problems associated with the earlier SD45 and a handful still roam the rails in the modern era.
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The SD50 would be the final locomotive to use the same 645 engine block introduced more than two decades before. The locomotive would be plagued with problems and some consider it the first step in EMD's slip in the build race with GE.
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Despite looking nearly identical to the SD50, with the introduction of the new 710 engine, the SD60 was a new locomotive inside.Continue to 13 of 20 below.
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With the addition of new crew comforts and cab controls, the SD60M marked the beginning of the modern era in locomotive design from EMD.
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Although only operated by one railroad initially, the SD60I, or isolated cab model, would pave the way for future quiet cab designs.
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Proving that good locomotives never die, Norfolk Southern has rebuilt many SD60 models into more efficient SD60E locomotives. Three special paint schemes have helped make these unique locomotives popular.
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In the mid 1990s the SD60 gave way to the SD70 series. With updated microprocessor controls, the SD70 was EMD's answer to the GE Dash 9 locomotives. Engines were available in standard, safety cab and AC traction motor versions.Continue to 17 of 20 below.
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Although the designation doesn't seem to indicate much of a change, the SD70M-2 offered several important changes from the SD70M. These improvements allowed the locomotives to remain compliant with more stringent emissions standards and
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The SD70ACe is the AC traction equivalent to the SD70M-2.
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The SD80MAC offered a 5000 hp locomotive with a proven engine and modern electronics. It was a more reliable alternative to the 6000 hp SD90MAC. Although only Conrail purchased the locomotives, years later their longevity over the SD90 models has proven the advantages of a safer path taken.
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When EMD promised a 6000 horsepower locomotive, several railroads expressed and interest. Few were ultimately convinced however and the trouble-prone locomotives suffered a rough reputation. Subsequent models lessened the power and promoted reliability more heavily.