metro Synonyms

underground tube subway subway system public transit mass transit railway rapid transit rail underground railway train track railroad station pentode MRT elevated railway light rail tramline underground railroad electric train big-city newspaper department subways urban transportation service rail rapid transit busline tracks commuter rail railway station monorail transit tram train track subterranean shuttle railroad municipal metropolitan metre tubing undergrow urban line magnetron maglev downtown passenger train choo-choo rail line belowground klystron