Night on the Galactic Railroad

Giovanni, a boy with too much work and too little money, finds himself aboard a train crossing the Milky Way. Campanella, his friend, is in the next seat. They follow the stars from station to station, talking with the passengers who come and go, until they reach a parting.

Miyazawa revised this all his life and never finished it, and perhaps that is why it stays with readers as a series of places rather than a plot. There are many voices, and they change quickly, which is precisely the situation speech bubbles were made for.