For the first six decades of the diesel era, the main goal of locomotive design was higher horsepower. Introduced in 1993, GE’s 4400 hp Dash 9 and its AC-motored sibling, the AC4400CW, were three times as powerful as a typical first-generation diesel and had 10%
more horsepower than their immediate predecessor, the Dash 8. A couple years later, GE and then EMD introduced 6000 hp engines, the first single-unit diesels to equal the power of the last and best steamers.
But what was thought to be a breakthrough turned out to be a flop. By the late 1990s, North American railroads had rejected the 6000 hp concept and concluded that the 4300-4400 hp diesel was the Goldilocks locomotive — not too big, not too small, but a versatile, just-right building block for multiple-unit lashups. The horsepower race was over.
The Dash 9, accordingly, turned out to be a best-seller. More than 3600 engines were sold by the end of production in 2004, and most are still hauling freight today. The Dash 9 was the last and best of GE’s third-generation diesels; it exemplified the modern loco_x0002_motive at the turn of the 20th century, with microprocessors ensuring that its 4400 horses were working as efficiently and as often as possible. It rode on GE’s brand-new HiAdTM trucks (for high adhesion), with computerized wheelslip control. Also new was a split
cooling system that reduced temperatures and prolonged engine life. The Dash 9’s wide-nosed North American cab, an option on earlier diesels, was standard equipment, solidifying the new look in road diesels. The Dash 9 was also the first GE diesel not offered with four-wheel trucks, recognizing that 6-axle, 4400 hp freight power was the new normal.