When the outlaws stop the train by blocking the tracks with trees, there is not a tree anywhere in sight.
During the attack on the train, the dead woman in the white dress blinks.
Maybe they used all the trees in the area to block the train.
When Joe first sees the abducted train he holds a red flower in his hand. The flower is clearly common poppy (bulka) which cannot be found in Americas (where the film supposedly takes place), only in Europe, Asia and North Africa (which is no wonder since the scene was filmed in Spain).
When Duncan reaches to scalp the Indian woman he killed; her eye twitches slightly before the camera cuts away.