It came up before, I think the reason McBain knew that the Sweetwater site would be valuable was that he was a former railroad man, the contract required a "station", Maybe McBain was more advanced on that score than we think. He had a large order of lumber delivered for the town who's to say he didn't previously order a load of rr ties and mine car rail and build a short stretch of siding for the station to be built up against.
The other solution would be symbolic, Cheyenne is banging against the future rr grade appearing in sandy silhouette.
well...oh..well...ah..ah.. anyway, super suggestions, thank you, but still have a problem to absorb them; I dont mind film bugs; for example I read that the harmonica used by Harmonica could not give the sound of the real sound given in the soundtrack; or that the song sung by Maurin was composed later then actaully sung in this story time frame; damn it!. It cant spoil or distract my passion. However, and it may appear as a paradox, this Cheyenne's banging on a rail is a tricky deal even in a tough imagination of this "prospect silhouette"; Sergio would be too trusting to an average cinema visitor (including me) to get this complex message.
Also your first alternative is hard to grasp for the audience; if the railroad is the symbol of something new, of the fundamental change of what we saw in the film before, it would not make sense to show us, that Mc Bain was a pre-pioneer not only in buing this land, but also a person going deep into the detail and building the "welcome" railroad. The sense of this story in this respect for me is that the lumber is the right element I can imagine - whatever and however large subject will be built on. Lumber and rail uttered together make
false notes to me; not mentioning the complexity of constructing that Mc Bain's rail track, however short it might be.
Taking into the account of Sergio's perfectionism, I do not beleive this rail banging being a film bug. I have to cite Cheyenne again,
"What the hell is this?"