EMD SD40 — LLMpedia

EMD SD40
Marty Bernard from U.S.A. · Public domain · source
Name	EMD SD40
Powertype	Diesel-electric
Builder	General Motors Electro-Motive Division
Builddate	1966–1972
Totalproduction	1,268 (SD40) + 43 (SD40A)
Aarwheels	C-C
Primemover	EMD 16-645E3
Aspiration	Turbocharged
Displacement	10,368 cu in
Cylcount	16
Poweroutput	3,000 hp
Tractiveeffort	90,000 lbf (starting)
Fuelcap	3,000–4,000 US gal
Locale	North America, South America

Contents

EMD SD40 The EMD SD40 is a six-axle, 3,000-horsepower diesel-electric road switcher built by General Motors's Electro-Motive Division in the late 1960s and early 1970s. It played a pivotal role in freight operations on railroads such as the Union Pacific Railroad, Santa Fe Railway, Southern Pacific Transportation Company, and Pennsylvania Railroad, influencing subsequent models like the EMD SD45 and EMD SD40-2.

Development and Design

The SD40 emerged from design work at Electro-Motive Division led by engineers influenced by earlier road locomotives like the EMD GP40 and EMD SD35 and by competing designs from General Electric and Baldwin Locomotive Works. Its core design incorporated the EMD 645 series engine, turbocharging technology refined during projects for Union Pacific Railroad and Chicago and North Western Transportation Company, and a six-axle AAR wheel arrangement chosen to meet tractive requirements of heavy freight services on corridors used by Penn Central Transportation Company and Missouri–Kansas–Texas Railroad. Styling and component layout were coordinated with suppliers such as Westinghouse Electric Corporation for electrical gear and Burlington Northern Railroad practices for crew visibility and maintenance access.

Standard SD40 specifications included the turbocharged EMD 16-645E3 prime mover, a DC traction motor arrangement supplied to classes ordered by Atchison, Topeka and Santa Fe Railway, Southern Railway (U.S.), and Northern Pacific Railway, and a fuel capacity tailored to long-haul operators like Canadian Pacific Railway and New York Central Railroad. Variants included the SD40A built for Illinois Central Railroad with an enlarged long hood tank and the SD40-2 influenced upgrades adopted later by Conrail and Seaboard System Railroad. Optional equipment packages were supplied for cold-weather service in Canadian National Railway territory and for mountain service used by Denver and Rio Grande Western Railroad and Great Northern Railway (U.S.).

Production between 1966 and 1972 resulted in large orders from North American carriers including Southern Pacific Transportation Company, Atchison, Topeka and Santa Fe Railway, Union Pacific Railroad, Illinois Central Railroad, and Conrail successor entities. The SD40's production run paralleled mergers and restructuring events such as the creation of Conrail and the mergers involving Penn Central Transportation Company and New York Central Railroad, which influenced fleet standardization decisions. Export orders and secondhand sales placed units with Ferrocarriles Argentinos, CP Rail, and private industrial operators, while some units were rebuilt under programs managed by General Electric competitors and National Railway Equipment Company.

Railroads used SD40s in manifest, coal, and intermodal service on mainlines owned by Union Pacific Railroad and Santa Fe Railway and in hump yard service at facilities operated by Norfolk and Western Railway and Burlington Northern Railroad. The combination of the 16-645 engine and six-axle trucks gave starting tractive effort useful for heavy unit trains run by CSX Transportation and Canadian National Railway, and fuel economy compared favorably to contemporaries from General Electric (locomotive) and Alco in mid-20th-century operating conditions. Reliability issues were addressed in field modifications by shops at Southern Pacific Transportation Company and by contractor rebuilds for Conrail and Illinois Central Railroad; crews frequently praised the model's flexibility for helper operations on grades common to Denver and Rio Grande Western Railroad and Colorado and Southern Railway routes.

Numerous SD40s have been preserved by museums and tourist railways including the California State Railroad Museum, Illinois Railway Museum, Illinois Central, and smaller heritage organizations across the United States and Canada. Preserved examples often receive restoration work from organizations such as National Railway Historical Society, Railway and Locomotive Historical Society, and volunteer groups associated with the Texas State Railroad and Grand Canyon Railway. Several units remain in active service with shortline operators like Genesee & Wyoming, industrial operators tied to US Steel facilities, and excursion operators supported by grants from state historical commissions such as those in Illinois and California.

Category:Electro-Motive Division locomotives Category:Six-axle diesel locomotives Category:Railway locomotives introduced in 1966