A Couple of Errors/Lose Ends

When Stewart and de Wilde first take the flatcar up to the track end there are a bunch of other guys riding the flatcar. When they finally reach end of track there are no people on the flatcar.

What powered the mill ore cars? Prior to pulling the lever there is no noise, smoke or apparent water power.

After Utica and the kid take off on the horses Stewart finds the empty sandwich box in the barn - but no money. It isn't seen again until the very end when Stewart takes it out of his saddlebags and gives it to the railroad boss.