The locomotive fundamentally consists of an NW2 hood, prime mover (a V12 EMD 567 diesel engine) and main generator on a long frame with road trucks (Blomberg Bs). The extra length was used for a large cab and an additional, full-width hood section, which contained a steam generator for passenger service. The boiler's exhaust was in the front center of the cab, between the front windows and exiting at the middle of the roof front.
The locomotives were delivered in GN's black diesel paint scheme of the time, but were later repainted in the bright, orange and green "Empire Builder" scheme. The short exhaust stacks as delivered were at some point replaced by standard conical EMD switcher stacks.
The first four locomotives were traded in by GN to EMD on new locomotives in 1965. The remaining three locomotives were sold to other railroads: #179 was sold to A.E. Staley Co. of Morrisville, Pennsylvania, keeping the same number; #180 was sold to the Clinchfield Railroad as their #361; #181 went to Anaconda Aluminium as their #100. The Clinchfield locomotive was scrapped; the Anaconda Aluminum unit is on display at the Whitefish, Montana depot in its GN "Empire Builder" colors, while A.E. Staley #179 is still in service as of 2004.