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EMD SD40-2 - A Locomotive Profile



Despite their massive numbers, if you looked more closely, few railroad's SD40-2s looked the same. One-of-a-kind paint schemes like this Union Pacific United Way engine didn't hurt either!

®2010 Ryan C Kunkle, licensed to About.com, Inc.

The SD40-2 added modular electronics to the already successful SD40 to create the best-selling EMD locomotive of all time.

Prototype History

Builder: General Motors, Electro Motive Division (EMD)
AAR Type: CC
Dates Built: 1972 - 1989
Number Built: 3,982
Horsepower: 3,000
Engine: 16-645E3
Length: 68ft 10in

EMD introduced its SD40 model in 1965 as a mid-range general service locomotive. Ironically, the "SD" which originally stood for Special Duty model of the 40 series locomotive was less specialized than the "General Purpose" GP40 which was marketed for fast freight service.

The SD40 was already emerging as the premier locomotive on the rails by the time EMD introduced its "-2" modular electrical package in 1972. This upgrade featured a modular electrical system that was faster and easier to replace and maintain. It was made available on all current EMD production models. Internally nothing else was changed, so EMD simply applied a "-2" suffix to the model number rather than a new designation. The practice ended with the SD and GP50 since the new package was by then standard.

Not only was the SD40-2 delivered to many railroads all across the United States, Canada and Mexico, versions were also shipped to Brazil and Guinea. In addition to seeing service in five countries and three continents, the locomotives were also built internationally in the United States (La Grange, IL), Canada (London, Ont.) and in Spain (MACOSA - Valencia).

On some locomotive models, like the GP40-2, their were very few visual changes between the original and -2 versions. The SD40-2 may have been the most distinctive change. Along with the enhanced electrical package, EMD also made its new HT-C six-axle trucks a standard option on this model.

These trucks required a longer wheelbase, so a larger frame was used. Since the carbody didn't grow, the SD40-2s were left with very large "porches" on the front and rear walkways. Some railroads opted not to have the new trucks, but their SD40-2s still came with the larger frame.

In addition to the trucks, there were several other options that railroads could specify: dynamic brakes, fuel tank sizes, short hood options (length and height) and smaller details like lights, bells, pilots, horns, etc. Some railroads, particularly in the western U.S., opted for additional radio control equipment for remote operation. The short hood of these locomotives was lengthened to accomodate the units. The longer noses were often dubbed "snoots" by workers. Wide cab SD40-2M and passenger power equipped SDP40-2 models were also offered.

The SD40-2 featured a turbo-charged 16 cylinder model 645E3 engine and produced 3,000 horsepower. It's principle competition were the C30-7 locomotives from General Electric, although these locomotives never came close to matching EMD's sales numbers. ALCO also offered 3,000 horsepower six axle "Century" class locomotives, the C-630.

The SD40-2 has enjoyed a reputation as a reliable workhorse. Many say it was the best locomotives ever produced by EMD or anybody. More than 40 years after their introduction, thousands of SD40-2s can still be found in service. In the 1980s and 1990s, many railroads rebuilt SD40s with the newer modular electronics into SD40-2s, but retaining their original carbodies and frames. SD45 and SD45-2 rebuild programs were also popular, downrating the 3600 horsepower units to 3000, often while retaining the distinctive carbodies.

These locomotives were ubiquitous in the 1970s and 1980s and look like they'll be anything but rare for more years to come!

Original Operating Railroads

  • Algoma Central - 6
  • Atchison Topeka and Santa Fe - 187
  • B&O - 20
  • British Columbia Ry - 17
  • Burlington Northern - 835
  • Canadian Pacific - 484
  • Chemin de Fer Boké - 3 (Guinea)
  • Chicago Northwestern - 135
  • Clinchfield - 5
  • Conrail - 167
  • Estrada de Ferro Carajás - 29 (Brazil - Final order of SD40-2s)
  • Ferrocarriles Unidos del Sureste - 4(Mexico)
  • General Motors - 10
  • Grand Trunk Western - 30
  • Illinois Central Gulf - 4
  • Kansas City Southern - 46
  • Kennecott Copper Corp - 7
  • Louisville and Nashville - 191
  • Milwaukee Road - 90
  • Missouri Kansas Texas - 37
  • Missouri Pacific - 306
  • Norfolk and Western - 162
  • Nationales de Mexico - 103
  • Oneida and Western - 8
  • Ontario Northland - 8
  • Quebec North Shore and Labrador - 44
  • Rede Ferroviária Federal Sociedade Anônima - 36 (Brazil - Built in Europe)
  • Rock Island - 10
  • Seaboard Coast Line - 36
  • St. Louis San Francisco - 8
  • Soo Line - 57
  • Southern - 128
  • Union Pacific - 686


The SD40-2 has been produced in several scales, along with the SD40. There were several options on these locomotives like high short hoods, dynamic brakes and numerous railroad specific details like horn, light, bell and plows.

The SD40-2 also underwent several design variations over its six year production including vent and door styles, etc. In some scales, many of these variations have been modeled, in others a little more detailing or "good enough" attitude will have to be exercised.

The list of models below is specific to just the SD40-2 itself. Some manufacturers have produced multiple runs capturing several of the common variations.

N Scale: Kato
HO Scale: Athearn, Bachmann, Broadway Limited, Kato
O Scale: Atlas O, Lionel

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