The Pullman Standard 50' PS-1 Box Car was one of the most successful freight car designs of the 1950s and '60s. While its standardized design contributed to ease of construction, it still offered the railroads and leasing companies a host of options that facilitated the cargo that the cars were destined to haul.
The typical RBL car was an insulated box car that was designed to carry canned goods that required protection from extremes of temperature, but not refrigeration. These cars had neither ice bunkers nor cooling units. The plug-style doors were normally used on these cars to ensure a tight body seal and to protect the loads from outside dust and dirt.
