What does it mean to dream about train?
A train often pictures a life-course set on a track and the pressure of timing, with a missed train a common image of lost chances.
Four ways to read it
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream.
Freud
Freud noted that missing a train can serve as a consoling dream about death or finality, the missed departure quietly reassuring the dreamer. More broadly the train, on its fixed track, can picture a course set by forces outside the dreamer.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
For Jung the train images a collective, scheduled course of life, a path shared with others and bound to its rails. Catching it marks moving with one's life-stage; missing it marks a fear of falling out of step with where one should be.
Jungian concept (our summary).Modern
Cognitively the train often pictures life direction on a set track and the pressure of timing. Missing it is a common anxiety dream tracking fear of missed chances, being late, or losing control over schedule and goals.
Continuity hypothesis (our summary).Mythological
As a modern vehicle of the journey, the train inherits the old motif of the set road and the fated departure, the boat or ferry that must be caught to reach the next shore, as Charon's ferry carried souls across the river. The fixed crossing one must not miss is an ancient image.
Bulfinch; Miller (1901).