looked at things like where should they locate waste water treatment facilities because of the impacts of climate change, what risks are likely to occur to their subway system because it's underground and already requires enormous pumping of water during certain large rainfall events."

VOA: standard.2010.06.14

the underground, or the subway, the Metro that we call it,

还有地下交通，比如地铁，我们通常称之为Metro，

旧金山的公共交通 - SpeakingMax英语口语达人