Like many other writers, I find trains useful. They feature in 5 of the 8 stories in my collection, and in Paradox, a poem from my pamphlet. There's the departure (leaving the old life behind) and the arrival (a new start) but the mode of transport has useful features too - a combination of constraint (tracks and timetables) and freedom; of aloneness and being in a crowd. And they have a rhythm.
Journeys are traditionally quests, but train journeys can be outside space and time. One of AL Kennedy's characters says "You can relax here - this isn't anywhere. What ever happens outside, there's nothing we can do about it right now". Kaye Mitchell says that for Kennedy's character trains are "free of the expectations and judgements of others, a space in which to meditate freely on the past and her possible future". One needn't devote a whole poem to them as Auden did with "Night Mail", mention of them's enough to be evocative - Carol Ann Duffy's "Prayer" includes "a man will stand stock-still, hearing his youth/ in the distant Latin chanting of a train."
Trains have an underworld - the Tube - a nightlife of couchettes, and they breed nostalgia in the form of steam locomotives. In this picture I was trying to do something clever - having the train move while the people's reflections in the train were static. Didn't quite work.
Of course, there are many books and essays on the use of trains in literature and film. Some places to start are