EMD SD90MAC
The EMD SD90MAC is a model of 6,000 hp (4,470 kW) C-C diesel-electric locomotive produced by General Motors Electro-Motive Division (EMD). It is, with the SD80MAC, one of the largest single-engined locomotives produced by EMD, surpassed only by the dual-engined DDA40X.
EMD SD90MAC and SD9043MAC | |||||||||||||||||||||||||||||||||
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UP 8540, an SD90MAC Phase II | |||||||||||||||||||||||||||||||||
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The SD9043MAC is the 4,300 hp (3,210 kW) variant, using a 16-cylinder 710G engine instead of the H-engine, which was originally intended as a temporary alternative while EMD tried to solve the H-engine's issues. However, the accompanying upgrade program was never utilized by its customers.
The SD90MAC's features include radial steering trucks with AC traction motors and an isolated safety cab which is mounted on shock absorbers to lessen vibrations in the cab. The SD90MAC, like the SD80MAC, SD70ACe, and SD70M-2, has a wide radiator section, nearly the entire width of the locomotive, which along with their size makes them easy to spot.
As of 2019, some SD90MACs are still in service on the Union Pacific. Norfolk Southern had rostered 110 SD90MAC locomotives purchased or traded from Union Pacific or the CIT Group respectively, that have now all been rebuilt as EMD SD70ACU locomotives. Canadian Pacific has also opted to convert their small fleet of long-stored SD90MACs into SD70ACUs as well.