8b9da35c_s___Travel_guide_at_Wikivoyage__UK
[US] subway, metro, local acronyms [Notes] "Subway" is used in Glasgow. "Metro" is also used in places like Montreal, Washington, D.C. and Newcastle upon Tyne. In many American cities the local public transport authority has a more or less well known acronym often ending in RTA (regional transit authority) or RT (rapid transit) as in e.g. BART in the Bay Area [UK] 
underground/tube
English language varieties – Travel guide at Wikivoyage
UK