When Cliff sets the dynamite charge it's dark. When he falls off his horse injured it's daylight. When the hands spot the fire it's dark again.
Dan Sheppard is seen taking photographs of Della price as she is swinging in a swing. The completed photograph is extremely sharp and clear even though she was in fast movement in mid swing. Action photography of this type was not possible during this time period. Subjects were required to remain perfectly still in order to capture a clear picture.
Whenever the train pulls into or out of Medicine Bow there is never any coal or wood in the fuel car.