What is another word for underground train?
Pronunciation: [ˌʌndəɡɹˈa͡ʊnd tɹˈe͡ɪn] (IPA) 
There are several synonyms for the term "underground train." Some common terms used include subway, metro, tube, and underground railway. The term subway is commonly used in North America, whereas metro is more commonly associated with Europe and parts of Asia. The term tube is often used in London to refer to their underground train system, whereas the term underground railway is used in some parts of the world. Other less common terms for an underground train include the rapid transit, mass transit, and underground railroad. All of these terms refer to a train system that runs underground in tunnels and is used as a form of public transportation.
