Greetings! I recently watched a movie and there was a story narrated in it, which goes like that: "... I remember once when I was your... and I was coming back from some place... a movie or something... and I was on the subway... and there was a girl sitting in front of me..." I know that the preposition 'on' is used with transport, so that's what we can see in a dialogue. But there are other prepositions that can be used like: in or by. For example: Where are you now? - I'm in the subway I get to work by subway. Could someone please give thorough explanation as to when use what preposition with transport. Thanks in advance!