fast track vs speed up

fast track

verb
  • To progress something with unusual rapidity. 

noun
  • A racetrack with optimum conditions for high speeds 

  • A railroad for express trains. 

  • The quickest or most direct method or path. 

  • A high-pressure or intensely competitive situation, particularly one characterised by rapid advancement. 

speed up

verb
  • To accelerate; to increase speed. 

  • To increase the speed of something; to make something go faster. 

How often have the words fast track and speed up occurred in a corpus of books? (source: Google Ngram Viewer )