The NWX was closely allied with the Chicago and North Western Railway as several officials also held positions at the C&NW. In 1946 the North American Car Company purchased the NWX, though all cars continued to carry the NWX reporting marks. During the 1950s the fleet was rebuilt at North American's Green Bay, Hudson, and Baraboo facilities. North American closed the Baraboo shops in December 1963 as new mechanical reefers were being purchased, and refurbishment of wood cars was no longer required. By 1978, only 25 NWX cars were left in service. When North American was taken over by General Electric Railcar in 1984, the few remaining cars were stored, and dismantled soon thereafter.
