Definition of train

• public transport provided by a line of railway cars coupled together and drawn by a locomotive; "express trains dont stop at Princeton Junction"
• a sequentially ordered set of things or events or ideas in which each successive member is related to the preceding; "a string of islands"; "train of mourners"; "a train of thought"
• a procession (of wagons or mules or camels) traveling together in single file; "we were part of a caravan of almost a thousand camels"; "they joined the wagon train for safety"