straggle vs walk the tracks

straggle

noun
  • An irregular, spread-out group. 

  • An outlier; something that has strayed beyond the normal limits. 

verb
  • To act in a disorderly and irregular way 

  • To stray, rove, or wander from a normal course and others of its kind. 

walk the tracks

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