hot water vs train wreck

hot water

noun
  • A dangerous situation; trouble. 

  • fierce criticism 

  • Used other than figuratively or idiomatically: see hot, water. 

train wreck

noun
  • Someone (especially a woman) who is unbalanced and considered a mess, a disaster, one who is suffering personal ruin. 

  • The aftermath of a train crash. 

  • A disaster, especially one which is large in scale and readily seen by public observers. 

verb
  • To ruin utterly and catastrophically, to cause to end in disaster. 

How often have the words hot water and train wreck occurred in a corpus of books? (source: Google Ngram Viewer )