These 50’-6” box cars were built in the 1960s and featured a combination of 8’-0” Youngstown sliding and plug doors. Combination door boxcars had the advantage of being both a standard box car with sliding door, plus having a larger opening for larger loads. The plug doors provided internal flush side walls along their location next to the sliding door. Having these flush side walls increased usable cubic feet capacity in the box car. Many of these box cars came with Hydra-Cushion or Keystone type cushioned underframes, and optional “damage free (DF)” load dividers.