地ち下か鉄てつ道どうちかてつどうMeanings1nounsubway; metro; underground railwayRefers to an underground railway system. Often interchangeable with 地下鉄 (ちかてつ), but 地下鉄道 can sound slightly more formal or technical.See also: 地下鉄東とう京きょうの地ち下