The Electromotive Division DD35 is an 8 axle, 5,000 HP dieselelectric locomotive built by EMD in 1963 and 1964. It used 2 16 cylinder 567D3A engines each rated at 2,500 HP to achieve a total of 5,000 HP.
In 1962, Union Pacific was looking for high horsepower diesel locomotives to replace the Gas Turbine Electrics they were using at the time, largely due to the Turbine's enormous appepitite for fuel. Specifically, UP waned a 3 unit locomotive set that could put out a combined 15,000 HP total.
At the time, EMD offered the 2,500 HP GP35 and SD35, niether of which could put out the needed amount of horsepower, so EMD designed a unit unlike anything ever before built. It was a large cabless booster unit that housed 2 2,500 HP 567's. Because it was so long, the unit rode on special flexicoil 4 axle D trucks, the first of their kind. Since it was basically 2 GP35's in one body, the unit was dubbed the DD35.
The idea was run the DD35's in A-B-B-A configuration with a GP35 on each end sandwhiching 2 DD35's in the middle to achieve 15,000 HP. 30 were built, 27 for Union Pacific and 3 for Southern Pacific. All were scrapped by 1977.
Seeking a more verstitle DD35, Union Pacific requested a unit with a cab so it could be operated independently and lead trains. Subsequently, EMD built 15 DD35A's equipped with cabs. Mechanically the same as DD35's, the DD35A differed externally in that it featured a GP35-style cab and large flared radiators (EMD was testing the flared radiator design for use on the future SD45). The DD35A's survived until 1981 when they were all scrapped.
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