articulated lorry vs wagon

articulated lorry

noun
  • A tractor-trailer or big rig, consisting of a semi-trailer and a semitruck pulling it; in American English referred to as semi-trailer truck or 18-wheeler. 

wagon

noun
  • A heavier four-wheeled (normally horse-drawn) vehicle designed to carry goods (or sometimes people). 

  • A vehicle (wagon) designed to transport goods or people on railway. 

  • A kind of prefix used in de Bruijn notation. 

  • Buttocks. 

verb
  • To load into a wagon in preparation for transportation; to transport by means of a wagon. 

  • To travel in a wagon. 

How often have the words articulated lorry and wagon occurred in a corpus of books? (source: Google Ngram Viewer )