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Class of diesel-electric locomotives From Wikipedia, the free encyclopedia
The SD45 is a six-axle diesel-electric locomotive class built by General Motors Electro-Motive Division between 1965 and 1971. It has an EMD 645E3 twenty-cylinder engine generating 3,600 hp (2,680 kW) on the same frame as the SD38, SD39, SD40, and SDP40. As of 2023, most SD45s have been retired, scrapped or rebuilt to SD40-2 standards.
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A total of 1,260 were built for American railroads before the SD45-2 replaced it in 1972, along with the related SD45T-2 'Tunnel Motor'.[citation needed]
SD45s had several teething problems. Reliability was not as high as anticipated; the twenty-cylinder prime mover was prone to crankshaft failure from engine block flex. Though it produced 600 horsepower (450 kW) more than the 16-645E3 in the SD40, some railroads felt the extra horsepower was not worth it, even after EMD strengthened the block to eliminate crankshaft failures. At low speeds when tractive effort was adhesion-limited, the SD45 provided no advantage over the SD40.[citation needed]
Buyers included the Burlington Northern, Southern Pacific, Santa Fe, Pennsylvania Railroad, the Great Northern Railway, Union Pacific and the Northern Pacific Railway. Many SD45s still exist, some rebuilt with sixteen-cylinder 645s for lease companies. SD45s and SD45-2s owned by Montana Rail Link retain their 20-cylinder prime movers. Wisconsin Central used to roster a large fleet of SD45s, but its sale to CN has resulted in the retirement of the entire fleet, with mass scrappings. Montana Rail Link is also starting to sell some for scrap.[citation needed]
EMD built seven examples of an experimental modification of the SD45, designated SD45X. The SD45X trialed several new features, including a more powerful EMD 645E3 engine producing up to 4,200 horsepower (3,130 kW) and a newly designed truck intended to have higher adhesion. Changes to the body included the use of different radiator fans and a flat rather than beveled end to the long hood. Six of the SD45X locomotives were purchased by the Southern Pacific Railroad, with the seventh kept by EMD.[3]
The Atchison, Topeka and Santa Fe Railway has rebuilt 115 units into what had become the EMD SD45u.[6] They were all renumbered as 5300-5483 between 1979 and 1989.[6][7]
In 1981, the Southern Pacific Transportation Company had rebuilt a single SD45 (SP SD45 #8837) into a single locomotive model designated the SD44R and numbered it #7399.
The Southern Pacific Transportation Company had rebuilt a total of 167 EMD SD45 units into EMD SD45R diesel locomotives at their own Sacramento Shops under the Southern Pacific's M-99 rebuild program and renumbered their units as 7400 through 7566. Most of them in their SD45 form were classified by the Southern Pacific as EF636-1, EF636-2, EF636-3, EF636-4, EF636-5 and EF636-6, but when they were all rebuilt under the Southern Pacific's M-99 rebuild program, they were classified as EF636LR-1, EF636R-2 and EF636LR-3.[8]
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