Bio Edit

The EMD (Electro Motive Division) SD40 is a type of six-axle, 16-cylinder, 3,000hp diesel locomotive built from 1966 to 1972 (though first introduced in 1964). It is the predecessor or precursor to the SD40-2, and the initial successor to the SD35. Over 1,268 units were built for multiple carriers across North America: 856 examples were built for American railroads, 330 for Canadian railways, and 72 for Mexican railways.
CNW 867 SD40

A pair of CNW SD40's leads a manifest train through East Chicago, IL in 1978. The lead unit (CNW #867) was the first production SD40 built, and was scrapped by 1980.

Many have since been scrapped, rebuilt, or upgraded to "Dash 2" specs, and are essentially SD40-2's. Some still retain their original designation and/or specifications, and are still in service on numerous Class 1 railroads; notably CSX #4617 and NS #3170. Many are retired, while some are preserved (such as IC #6071: the first SD40 ever built).

Many are also currently in lease service, while others are now in service with various shortlines.


Beginning in the early 1960's, EMD began to set a new milestone by upgrading their existing, long-running, 567 series engine line designed with the more powerful and larger 645 series. By increasing the bore and stroke of the existing two-stroke, turbocharged, 16-567D3 series, and giving it a 645 cubic inch displacement, the highly-acclaimed 16-645E3 prime-mover was born. In addition to a 16-cylinder prime-mover model, 8-cylinder, 12-cylinder, and 20-cylinder variants were built to accompany the ever-increasing demand of high-horsepower for single-engined diesel locomotives by most railroads, for trains were becoming longer and heavier and the aging, traditional, roots-blown 1,500-1,800hp road-switchers and road-diesels weren't quite up to the task to meet demands. Despite the preceding GP30, GP35, and subsequent SD35 models having made their mark, they were already beginning to reveal their imminent defeat, for 2,250-2,500hp range (along with the failures of the 35 Series electrical systems) wasn't enough to meet the power hungry demands for railroads. Having a large consist assigned to longer trains meant higher fuel and opera
UP SD40X units

A pair of UP SD40X testbeds. UP #3045 was one of the several built with distinct flared radiators found on all SD45 units.

ting costs, which was something that railroads weren't quite fond of, considering their rough competition with trucks and automobiles forced many railroads into bankruptcy at the time. Furthermore, the initial aim was to replace an entire locomotive consist on a two for one basis, or on a five to three. The solution to these problems were made with the introduction of two revolutionary models: the SD45 and SD40, which captured the eyes and ears of railroad crews and employees with their thunderous 645 engines, which gave a very noticeable presence; especially while in full throttle or at notch 8, along with their fairly new, modern, and simplistic designs which first debuted on the less-popular and successful SD35 and SD28 (besides their four-axle counter-parts). 

Beginning in 1964, several test-beds (known simply as the "SD40X", but not to be confused for the SD50 test-beds built years later) were constructed and assembled at EMD's LaGrange, IL facility between July 1964 and April 1965, and were leased to Union Pacific (UP) and the Gulf, Mobile, and Ohio (GM&O); eight were given to UP, one for GM&O for testing and evaluation purposes. All were all built on an SD35 frame, and were often labelled as an "SD35X", though the term was more widely used to help differentiate between the SD50 test-beds built and leased (but eventually sold) to the Kansas City Southern (KCS 700-703) in 1979. Upon the completion of the tests came many positive results, and by the end of 1965, the SD40's final design schematics were in-place. By early 1966, the first orders were placed by the Chicago and North Western (CNW), and by the end of the year over a dozen or so were built. Later on, more and more customers grew interested in purchasing the model once they saw its success on neighboring and rival systems. Companies like the Baltimore And Ohio (B&O), Chesapeake And Ohio (C&O), and the Pennsylvania Railroad (PRR) were among others who caught on to the SD40's success with its winning combination of high horsepower, reliability, and versatility which made it an instant choice for power when operating in harsh weather conditions throughout the Northeastern United States (besides the Midwest, for companies like the Milwaukee Road and Grand Trunk Western acquired a decent number of units for operation in the Great Lakes region; where lake effect snow caused twice the amount of problematic issues with preceding models from other builders).

Over the years, the model proved to live up to its expectations, for it ultimately outsold its competition from rivals ALCO and GE, who further declared defeat against EMD's reign of success and leadership in the domestic diesel locomotive market, which furthermore prompted both companies to retreat from focusing strictly on the foreign export markets. Though the success of the SD40 defeated the competition, it unfortunately prompted an untimely end to an iconic builder of steam locomotives and early diesel locomotive models. In 1969, ALCO ultimately closed their doors of their Schenectady, NY facility, furthermore spelling the end of ALCO's presence in the domestic market and the beginning of subsidiary MLW's (Montreal Locomotive Works') rise to fame in Canada in the following decades.

By early 1972, over 1,000 units were produced by the time of the SD40's successor; the SD40-2, debuted. The SD40-2 furthermore peaked sales even higher than before when EMD revealed the internal, almost unnoticeable change: the revolutionary "Dash 2" electrical system from EMD's "Dash 2" line. With its well-organized panels, modules, and circuit boards, the otherwise tedious and messy electrical system found on the original SD40 became one of the most easily maintainable electrical systems found on all diesel locomotives among mechanics and electricians. Ironically, many customers whom originally placed orders on SD40's received SD40-2's instead, and even preferred the "Dash 2" variant of the SD40 more-so than its initial predecessor.

By 1986, nearly 4,000 SD40-2's were built and assembled; outselling its predecessor almost entirely. Furthermore, many existing true or straight (original) SD40 units were then upgraded to "Dash 2" specifications, and were ultimately re-classed as an "SD40-2" following the debut of the 50 series locomotive models and the discontinuation of the 645 series line from the primary domestic locomotive market, prior to the introduction of the 710 series beginning with the SD60. Thus, making the 645 locomotive models part of the secondary market, furthermore prompting discounted sales on "Dash 2" electrical systems and components for easy conversion of original SD40 units.

Spotting FeaturesEdit

Although externally similar to the SD40-2, it is actually completely different internally (when referring to the electrical systems). The only known external differences between the latter of models being the length of the frame, truck model ("Flexicoil" as opposed to "HTC"), and the lack of a water-level sight glass present on all "Dash 2" models.

Versions and VariantsEdit

SDP40: Passenger variant equipped with steam generator (some have been rebuilt to SD40-2 specs). 

SD40A: Specialty variant built for traveling longer, remote distances.

SD40-2: Successor to the original model, though considered to be independent from the original, and part of the "Dash 2" line. 

SD40R: SP rebuilds of SD40 units built to "Dash 2" specs from private contractors. 


Model SD40
Production Dates 1966-1972
Total Built 1,268+ (including specialty and model variants)
Length 65' 8" (some measured at 70' 8")
Width 10' 0"
Height 15' 514"
Wheel Diameter 40"
Engine (prime-mover) 16-645E3
Horsepower Rating 3,000 (3,125-3,200 in some cases)
Alternator AR10
Traction Motors D77
Weight x 1,000lbs. 360,000
Top Speed 65mph
Fuel Capacity 3,200 US gallons


CNW #867; while being the first production SD40 unit built, is often neglected, for GM&O #950 (now IC #6071) is regarded as being the very first unit built (despite being a preproduction test-bed or prototype).

EMDX #434 became GMO #950 after having completed demonstrations with the ATSF. Years later after the IC-GMO merger, the unit was rebuilt and became IC #6071: an "SD40A" or "SD40-2R" (per classification under the railroad). The SD40 was then donated by CN to the Illinois Railway Museum in 2010.

EMDX 434A-434G became UP #3040-3046. All seven of the UP SD40X units were then auctioned-off by 1989-1990, however. UP #3046 now currently resides with the Wheeling And Lake Erie (WLE/WE) and is classified as an SD40-3 after having been rebuild by NRE in 2000, while one unit was acquired PLM (a subsidiary of CITX), and was scrapped in 1995, however. All others were unfortunately scrapped, making WE #3046 the sole survivor.

CSX SD40 #4617 (originally C&O #7534), was the very last locomotive to remain in C&O paint (Chesapeake and Ohio; a CSX predecessor) until 2009, when the patched unit finally received CSX's current YN3 paint scheme. It is also the very last and only true or non-modified SD40 on CSX's roster.

The N&W also owned several standard-hood SD40 units as opposed to the common "hi-hood" configuration; some which were rebuilt from SD35 units. Several low-nose or "low short-hood" (standard hood) SD40-2 units were also acquired prior to the Norfolk Southern merger as well.

Illinois Central (IC) SD40 #6071 (originally EMD #434, later Gulf Mobile & Ohio #950) is the very first SD40 ever built, and was originally built on a SD35 frame with SD40 hood features present on the production units. The other testbeds, however, were built with SD45-style radiator sections. What else is unique about this particular locomotive, is the fact that it was Operation Lifesaver-sponsored while it was under the ownership of the IC prior to its retirement by CN years after the merger. It now currently resides at the Illinois Railroad Museum in its Operation Lifesaver scheme, and is classified as an "SD40A" (not to be confused for the actual model of the same name).


Sources Edit