50' Box cars were the backbone of the US Railroad fleet from the 1950s to the mid 1970’s and could be found in use by nearly all US Railroad operators from large companies to smaller local lines. The cars could be found being hauled by 1st and 2nd generation Diesel locomotives carrying all manner of goods. As different operators had many different requirements many different versions could be found including versions with sliding doors and plug doors and with or without roof walks.