Noun
freight car without permanent sides or roof
Source: WordNetThe Chicago Great Western Railway filed a US federal patent in 1938 on their method of securing each trailer to a flatcar using chains and turnbuckles. Source: Internet
"Piggy-back" trains are the fastest growing type of freight trains in the United States, where they are also known as " trailer on flatcar " or TOFC trains. Source: Internet
The bust was moved from set to set on a flatcar. Source: Internet