power supply vs rail

power supply

noun
  • That part of a piece of electronic apparatus that provides appropriate voltages for the rest of the electronics from the connected AC source. 

  • A source of power such as the mains or a generator. 

  • Used other than figuratively or idiomatically: see power, supply. 

rail

noun
  • A conductor maintained at a fixed electrical potential relative to ground, to which other circuit components are connected. 

  • A horizontal bar extending between supports and used for support or as a barrier; a railing. 

  • A large line (portion or serving of a powdery illegal drug). 

  • A railroad; a railway, as a means of transportation. 

  • Any of several birds in the family Rallidae. 

  • One of the lengthwise edges of a surfboard. 

  • A horizontal piece of wood that serves to separate sections of a door or window. 

  • The metal bar forming part of the track for a railroad. 

  • A vertical section on one side of a web page. 

verb
  • To enclose with rails or a railing. 

  • To range in a line. 

  • To place on a track. 

  • To sexually penetrate in a rough manner. 

  • To travel by railway. 

  • To complain violently (against, about). 

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