The GE AC4400CW is a 4,400 horsepower (3,300 kW) diesel-electric locomotive that was built by GE Transportation Systems between 1993 and 2004. It is similar to the Dash 9-44CW, but features AC traction motors instead of DC, with a separate inverter per motor. 2,598 examples of this locomotive were produced for North American railroads. As a result of more stringent emissions requirements that came into effect in the United States on January 1, 2005, the AC4400CW has been replaced by the GE ES44AC.
The AC4400CW was the first GE locomotive to offer an optional self-steering truck design, intended to increase adhesion and reduce wear on the railhead. This option was specified by Canadian Pacific, Cartier Railway, CSX, Ferromex, Ferrosur, and KCS.
CP AC4400CW #9560 and CP SD40-2 #6029 head west towards the NS Elkhart Yard, 2009.
Kansas City Southern AC4400CW no. 4575 with self-steering trucks in October 2014
CSX ordered many of its AC4400CW locomotives with 20,000 lb (9,100 kg) extra weight to increase tractive effort. These same units were also modified in 2006-2007 with a "high tractive effort" software upgrade. CSX has redesignated these modified units from CW44AC to CW44AH. Union Pacific ordered many of their AC4400CW's with Computerized Tractive Effort software, giving them the designation of AC4400CW-CTE. This software was carried on from their AC4400s and is now standard on Union Pacific ES44AC's.