Once Upon a Time in the West (1968)

Revealing mistake: Jack Elam gets bothered by a fly crawling over his face (nice stunt, actually). When the fly moves over the bench, just before he catches it with the muzzle of his gun, look at the hind legs. You'll notice that the fly is dead. (00:07:50)

NancyFelix

Frank: What do you want? Who are ya?
Harmonica: Dave Jenkins.
Frank: Dave Jenkins is dead a long time ago.
Harmonica: Calder Benson.
Frank: What's your name? Benson's dead, too.
Harmonica: You ought to know, Frank, better than anyone. You killed 'em.

Trivia: While Morton's private train plays a key role in the movie, and the train moves several times, the train's engineer and fireman are never shown, nor is any reference ever made to them.

Question: At first it seemed Cheyenne didn't know harmonica man, but later in the movie they help one another once to get the $5,000 from Cheyenne's bounty. Then Cheyenne rescues harmonica man from the train. And finally Cheyenne didn't want harmonica man to see him die they were leaving together I just think they knew each other and this was planned?