chargehand vs overman

chargehand

noun
  • A person who is in charge of a small group of workers; a lesser foreman. 

overman

noun
  • A person who supervises others; a supervisor, especially in a mine. 

  • A person with great powers; a superman. 

verb
  • To provide with too many personnel; overstaff. 

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