I’d appreciate some clarification.
9-44CWs use Direct Current (DC) traction motors while AC4400CWs use Alternating Current traction motors. They are essentialy the same locomotive, but with different motors.
The AC4400CW uses AC power, as BigBoy said, and it has a large box behind the cab, on the walkway, housing the Inverters that convert DC power to AC power.
Greg
I thought that they looked an awful lot alike, now I know why