Back to the Future Part III (1990)

Though Doc asked Marty not to come back for him, Marty does go back anyway, because he and the 1955-Doc find out that Emmet Brown was killed shortly after the writing of the letter (by Mad Dog Tannen, the great-grandfather of Biff).
Right after the time-jump, the DeLorean is attacked by Indians who put an arrow to the gas tank, the fuel goes away.
Doc finds a way to solve that: they must kidnap a train and accelerate with that above 88 mphs.
Doc saves the new teacher of the town, Clara Clayton, who was supposed to die, and falls in love with her.