These 51’ mechanical reefers with rivet sides, single plug doors and no roofwalks are painted with yellow sides, black roofs and ends, and run on Roller Bearing trucks. They were built in December 1962 by Pacific Car & Foundry for North American Car Corporation (NIRX) and leased to Canadian National. CN purchased the cars shortly thereafter and renumbered them in the 231000-231074 series during the major renumbering in 1965. They display the “wet noodle” logo with the English spelling of “Canadian” on both sides of the car. Although these cars were painted black and yellow, CN started painting their mechanical reefers silver/aluminum soon after the arrival of these cars.