Ginga Tetsudou Monogatari: Wasurerareta Toki no Wakusei

An OVA in the Galaxy Railways series takes place in a future where planets are linked by a vast railway system. The Galaxy Express 999 crashes on an unknown planet, with The Conductor, Killian, Maetel, and Tetsuro, a ten-year-old boy with a kind nature, aboard. The SDF Sirius Platoon is tasked with rescuing them before the Herise Time Mystery, a disruption in time and space, occurs again.