Operating Era: 1922-1975. Now includes our one-piece roof frame. Union Refrigerator Transit Lines, American Refrigerator Transit, Great Northern/ Western Fruit Express. AC&F produced a standard reefer design from 1911-1928. The first version had 5'10" doors, ladder grabs and a 30" center sill. The cars were sold to American Refrigerator Transit and Union Refrigerator Transit. URT's cars were sold to Great Northern in 1920. ART 's first steel underframe cars were this type, 1,000 cars delivered in 1911. They were slightly different from URT; therefore the Ia designation. ART ordered another 3,400 cars in the following years but they differed in side sheathing length and had brake stands (see kit 6501).The cars ran as built into the mid-1920's when smaller heralds were applied. The cars ran to about 1950. Our kit covers the 1911-1920's period.