One of Buster Keaton's craziest stunts
This is real footage from 100 years ago. That is a real man, on the front of a real train, actually moving down the track.
It comes from his 1926 film The General, and it is one of the most dangerous stunts he ever performed.
Keaton's character is riding on the cowcatcher as it moves down the track. Ahead of him, the enemy has laid a heavy railroad tie across the rails to derail the train. His plan, performed for real, is to throw the beam in his hands at exactly the right instant so that it strikes the other beam and knocks it clear of the track before the wheels reach it.
Think about what that required: he is perched on the front of a real, moving train, with nothing holding him on. If his throw had been slightly off, or if he had lost his balance, he would have slid straight down onto the rails. There was no harness, no padding, and no way to fake it. He had to do it, and get the timing perfect, while the locomotive kept rolling forward.
Keaton risked his life like this for real, again and again, and never once let it show on his famous deadpan face.