 
 <translate> This list of metro systems includes electrified rapid transit train systems worldwide. In some cases, metro systems are referred to as subways, U-Bahns or undergrounds. As of October 2014, 157 cities in 55 countries around the world host the approximately 160 metro systems that are listed here. The London Underground first opened as an "underground railway" in 1863 and its first electrified underground line opened in 1890, making it the world's first metro system. The metro system with the longest route length is the Shanghai Metro; the busiest one is the Beijing Subway; and the one with the most stations is the New York City Subway.

Answer this question: when was first metro train started in world? Let's give stream of consciousness first: <hau> Wannan jerin tsarin metro ya hada da tsarin jirgin kasa mai saurin lantarki a duk duniya. A wasu lokuta, ana kiran tsarin metro a matsayin jirgin karkashin kasa, U-Bahns ko karkashin kasa. Ya zuwa Oktoba 2014, birane 157 a cikin ƙasashe 55 na duniya suna karɓar tsarin metro kusan 160 da aka lissafa a nan. An buɗe London Underground da farko a matsayin "hanyar jirgin ƙasa" a cikin 1863 kuma an buɗe layin jirgin ƙasa na farko a cikin 1890, yana mai da shi tsarin metro na farko a duniya. Tsarin jirgin karkashin kasa da ya fi tsayi shi ne Shanghai Metro; wanda ya fi cunkoso shi ne Beijing Subway; kuma wanda yake da tashoshi mafi yawa shi ne New York City Subway.  Amsa wannan tambayar: Yaushe ne jirgin kasa na farko ya fara aiki a duniya? Bari mu ba da rafi na sani na farko: 