The North Western Refrigerator Line (NWX) was a Chicago, Illinois-based private refrigerator car line established in 1924, one of the last such companies to be formed. Between 1924 and 1940 the company acquired more than 3,000 new wood refrigerator cars originally built by the American Car & Foundry Company, and leased the former Ringling Brothers Circus railroad car plant in Baraboo, Wisconsin to serve as a car shop.

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.

Notable Number Series

Series 600-699 were rebuilt in 1955. AAR class RS.

Series 4000-5499 were built in 1926 as series 6001-6200. AAR class RS.

Series @ 10530 were rebuilds in 1952. The cars received Improved Dreadnaught ends and diagonal braces but retained the wood sides. AAR class RS.

Series 12000-12300 were built in 1931 and rebuilt by Pacific Car & Foundry in 1953. The rebuilding included steel roof and ends, a power Equipco hand brake, and exposed side sills. AAR class RS.

Series 15000-15999 were built in 1927 by American Car & Foundry as series 6701-7720 and renumbered by 1937. AAR class RS.

Paint Schemes

The original paing scheme was grey.

The popular green and yellow paint scheme was introduced in 1953.