trackbed vs vat

trackbed

noun
  • The layer of gravel or other foundation on which a railway track is laid. 

  • The land on which a railway (especially one that has been closed or dismantled) was built; the roadbed for a railroad. 

vat

noun
  • A square, hollow place on the back of a calcining furnace, where tin ore is laid to dry. 

  • A vessel for holding holy water. 

  • A large tub, such as is used for making wine or for tanning. 

verb
  • To put into a vat. 

  • To blend (wines or spirits) in a vat; figuratively, to mix or blend elements as if with wines or spirits. 

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