轻轨

轻轨	qīng guǐ	light rail; transit system (underground, at street level or elevated); streetcar; metro (abbr. for 轻型轨道交通)
轻	qīng	light / easy / gentle / soft / reckless / unimportant / frivolous / small in number / unstressed / neutral / to disparage
轨	guǐ	(bound form) rail; track; course; path