boxcar       
noun [ C ] US uk/ˈbɒks.kɑːr/ us/ˈbɑːks.kɑːr/
 (铁路上运送货物的)棚车
a railway carriage with a roof, used for carrying goods
  The boxcar left the train tracks but it remained upright.
 - More examples
 - They crash into each other, like runaway boxcars hurtling off different trains.
 - He said undocumented immigrants are in constant need of assistance, with plights ranging from getting caught in sealed boxcars to suffering snake bites.
 - The world's largest smelter piped enough metals-laden slag into the river to fill four boxcars each day.
 - Jackson grew up in a converted boxcar in southern Illinois.