地铁 metro/underground railway/subway
城市轨道交通 urban rail transit/mass transit
设计使用年限 designed lifetime
运营概念 operation concept
旅行速度 operation speed
限界 gauge
正线 main line
辅助线 assistant line
联络线 connecting line
试车线 testing line
轨道结构 track structure
轨距 gauge of track