footing vs trackbed

footing

noun
  • The thickened or sloping portion of a wall, or of an embankment at its foot; foundation. 

  • Stability or balance when standing on one's feet. 

  • A narrow cotton lace, without figures. 

  • A footprint or footprints; tracks, someone's trail. 

  • The finer refuse part of whale blubber, not wholly deprived of oil. 

  • The act of putting a foot to anything; also, that which is added as a foot 

  • The act of adding up a column of figures; the amount or sum total of such a column. 

  • A double-check of the numbers vertically. 

  • A ground for the foot; place for the foot to rest on; firm foundation to stand on. 

  • A standing; position; established place; foothold. 

  • A relative condition; state. 

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. 

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