The AC6000CW sprung from the horsepower wars of the late twentieth century. As GE and EMD fought to best each other with single-unit engines boasting more and more horsepower, General Electric introduced the AC6000CW Convertible. These initial AC-traction-motored engines provided 4,400 horsepower, but were designed to be converted to the twin-turbo 6,000 horsepower Deutz 7HDL16 diesel motors as soon as the motors were ready. The Union Pacific was the only taker for the convertibles, purchasing a total of 106 units.
The first production 6,000-horsepower engines were delivered in December 1995. The main spotting features of both the regular and convertible AC6000CW's are their huge radiators that hang out over the walkways at the rear of the body, and a step-up in the walkway on the right side of the body, to clear the twin air reservoirs. An immense 5500-gallon fuel tank was needed to satisfy the thirst of 6,000 horses, and that forced GE's designers to move the air reservoirs atop the fuel tank and raise the walkway to clear them.
As it turned out, American railroads decided a 4,300-4,400 horsepower engine was the optimum building block for multiple-unit consists, and the craze for 6,000 horsepower locomotives faded. None of the convertible models was ever upgraded to the larger motor. Significant fleets of AC6000CW's were purchased only by the Union Pacific and CSX before the last of 207 units produced was delivered in 2001.