freightwagon vs tractor-trailer

freightwagon

noun
  • Any vehicle, such as a cart, wagon, lorry, truck, or boxcar, used for carrying or transporting goods; a cargo truck. 

tractor-trailer

noun
  • A large truck consisting of an engine and cab section (the tractor) and a cargo-carrying semi-trailer or trailer. 

How often have the words freightwagon and tractor-trailer occurred in a corpus of books? (source: Google Ngram Viewer )