OPERATING ERA: 1944 to 1972. This Kit now comes with our new One-Piece Roof Frame. The Rock Island converted B-2 Box Cars into Stock Cars starting in 1944. The Double Deck cars were also converted in 1944, with 86 being done. These cars, series #79701-79800, had dutch stock doors with metal v straps. When the metal roofs wore out, they were removed, leaving the wood under-roof. It is not known how many cars received this treatment.