pier vs railbed

pier

noun
  • A structure supporting the junction between two spans of a bridge. 

  • A similar structure, especially at a seaside resort, used to provide entertainment. 

  • A rectangular pillar, or similar structure, that supports an arch, wall or roof, or the hinges of a gate. 

  • A raised platform built from the shore out over water, supported on piles; used to secure, or provide access to shipping; a jetty. 

railbed

noun
  • The substructure of a railway, underlying the tracks; the roadbed of a railroad. 

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