EMD E1A/E1B

The EMD E1 was among the earliest passenger diesel locomotives produced by the Electro-Motive Division of General Motors, emerging in 1937 as a direct successor to the experimental EA units built for the Baltimore and Ohio Railroad. The E1 represented a formative step in EMD's effort to establish a standardized line of passenger power, and all examples were delivered to the Atchison, Topeka and Santa Fe Railway. The Santa Fe was a particularly enthusiastic early adopter of diesel passenger power, and the E1 units were put to work on some of the railroad's most prestigious runs, including the Super Chief, the famous all-Pullman streamliner connecting Chicago and Los Angeles. EMD produced eight A units and four B units in the E1 series between 1937 and 1938, for a combined total of twelve locomotives. The A units, designated E1A, carried a full cab with crew accommodations, while the B units, designated E1B, were cabless booster units intended to operate in tandem with an A unit to provide additional tractive effort on demanding long-distance runs. The Santa Fe typically paired these locomotives in A-B or A-B-A configurations to handle the weight of the luxury trains for which they were assigned. The E1 holds a significant place in American railroad history as part of the generation of early EMD passenger diesels that demonstrated the practical and economic viability of diesel traction for mainline passenger service. Although the units were eventually superseded by later and more refined EMD models as the E series evolved through subsequent lettered variants, the E1 contributed directly to the operational experience and customer confidence that allowed EMD to refine its product line and ultimately displace steam traction across the country. No E1 units are known to have been preserved.

Each E1 locomotive was powered by two Winton 201-A prime movers, a sixteen-cylinder two-stroke diesel engine that had been developed in the early 1930s and was central to EMD's initial foray into diesel locomotive production. The combined output of the two engines gave each unit a total of 1,800 horsepower, which was transmitted to the wheels through a direct current electrical transmission system typical of diesel-electric locomotives of the era. The wheel arrangement was A1A-A1A, meaning each three-axle truck had its center axle unpowered, a configuration chosen to distribute the locomotive's weight more effectively over the track while keeping the overall axle loading within acceptable limits for the passenger routes the units served. The carbody of the E1 followed the streamlined aesthetic that was fashionable in the late 1930s, featuring a smooth, nose-forward design that complemented the stainless steel passenger equipment with which the Santa Fe operated its premier trains. The overall layout and mechanical architecture of the E1 were closely related to those of the EA and EB units that had preceded them, and the lessons learned from those earlier locomotives informed refinements in the E1's construction. The design established conventions in truck configuration, engine arrangement, and carbody styling that would carry forward through many subsequent EMD E series models.

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