What is another word for railroad tunnel?
Pronunciation: [ɹˈe͡ɪlɹə͡ʊd tˈʌnə͡l] (IPA) 
A railroad tunnel, also known as a train tunnel, is a passage that allows trains to travel through mountains or under cities. There are several synonyms for railroad tunnel including chute, cutting, gallery, passage, shaft, subway, and underpass. A chute is a steep, sloping tunnel that allows trains to descend quickly. A cutting is a trench-like excavation that is commonly used to make way for railway lines through hilltops or mountains. Gallery is a term used for tunnels that run horizontally through mountains. The passage is a term used for tunnels that are created to divert water or other natural phenomena away from railway tracks. A subway is an underground railway tunnel that runs beneath cities. Lastly, an underpass is a tunnel created for vehicles or pedestrians to pass under when a railway line runs on top.
