Term: flatcar (railroads)
a type of rolling stock, which can be a flat-bottomed car with no sides on which freight (including intramodal shipping containers) can be stacked. A bulkhead is a flatcar with walls on the front and back. A center-beam bulkhead is a bulkhead flatcar with
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[Source: "Rail terminology" at Wikipedia (http://en.wikipedia.org/wiki/Rail_terminology)]