Galaxy Express 999

is a manga written and drawn by Leiji Matsumoto, as well as various anime films and TV series based on it.

Plot
An impoverished ten-year-old named Tetsuro Hoshino desperately wants an indestructible machine body, giving him the ability to live forever and have the freedom that the unmechanized don't have. While machine bodies are impossibly expensive, they are supposedly given away for free in the Andromeda galaxy, the end of the line for the Galaxy Express 999, a space train that only comes to Earth once a year.