City 60097 - mod - What power source should I use ?

I just finished my new inter-terminal train for my Lego City airport project, but something went in my mind. Between battery box and 9v tracks (which Jangbricks used to power one of his trains), which power source should I put, since I want to light up the interior ? Please note that I gonna need some cables and LED for the second option. submitted by /u/Obvious-Pride-1979 [link] [comments]