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Builder :
General Motors Electro-Motive Division
Electricity :
Length :
80' 2"
Width :
10' 3 1/8"
Height :
15' 9"
Weight :
210 tons
Cylinders :
Wheel Diam :
Fuel Tank :
5800 gal
Max Speed :
75 mph
Horsepower :

Development of an all-new prime mover capable of producing 6000 h.p. gave Electro-Motive its first production, four-cycle engine: the 16-cylinder, 265mm-bore, 300mm-stroke GM-16V265H. The power plant for the highly anticipated SD90MAC, the 265H evolved from concept to completion in a remarkable 18 months. However, teething pains with the new prime mover bogged the project down. Rather than delay the SD90MAC indefinately, EMD struck an unprecedented compromise. The first SD90MAC's would be built with 4300 h.p. 16-710G3 engines and repowered and upgraded with the 6000 h.p. 265H when the new engine was put into production. Enter the SD9043AC.

For a temporary model, the SD9043AC has fared relatively well, selling a total of 410 units to date. Union Pacific has thus far assembled a fleet of 309 'upgradable' SD90MAC's. The only other railroad to order the model so far has been Canadian Pacific, with 61 units. Rounding out the 710-powered SD90MAC population are 40 marron and grey CEFX units built for the lease fleet of CIT Financial. Not surprisingly most of their time has been on lease to UP and CP.

The long awaited H-engine made its debut in September 1996 as EMD displayed UP 8160, the first of eight preproduction 6000 h.p. SD90MAC's in Chicago. Dual exhaust stacks of the twin-turbo 265H engine and the beveled edges of the engine compartment differentiate the 6000 h.p. SD90MAC from its 710-powered, upgradable kin.

In the summer and fall of 1999, London and Schenectady out-shopped UP SD90MAC-H II's 6522-8561, but the 40 units were held for several months awaiting design improvements, delivery commenced in February 2000. Canadian Pacific, the only other road to receive SD90MAC-H II's, cut its order back from 20 units to 4, which were built in late 1999.