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 locomotive 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.
Did You Know?
Norfolk Southern Dash 9s have software that downrates their motors to 4000 hp in order to reduce engine wear and fuel consumption. If needed, however, the extra 400 horses can be accessed with the flip of a key switch.