From the Super Mario Wiki, the Mario encyclopedia
Rainbow Coaster is a course in Mario Kart Arcade GP. Rainbow Coaster gives a very rollercoaster-like experience, much like the Mario Kart DS Rainbow Road. It also features a teleporter at mid-stage. Mario Kart Arcade GP 2 has the same tracks as its predecessor, but no coins at the Jumping Shortcut.
Rainbow Coaster and Rainbow Downhill are the Arcade GP equivalents of Rainbow Road.