Ginga Tokkyuu Milky☆Subway Movie: Kakueki Teisha Gekijou Yuki

Six delinquents are given a painfully simple community-service assignment: clean an abandoned train. The job stops being boring the moment the train suddenly powers up and launches into space, carrying all six away with no idea how to stop it or where it is going.

Between arguments, panic, and desperate attempts to control a train that refuses to cooperate, they discover that being trapped together is not even the worst part. Every stop can bring a stranger problem than the last, and newly revealed pieces of their journey make reaching the end require far more than a mop and bucket.