steam engine vs steam train

steam engine

noun

  • A steam locomotive. 

  • A piston engine driven by steam (as contrasted, for example, with a steam turbine). 

  • Any heat engine that uses steam as its primary working fluid to do mechanical work. 

steam train

noun

  • A train pulled by a steam locomotive. 

How often have the words steam engine and steam train occurred in a corpus of books? (source: Google Ngram Viewer )