Factual error: In one scene where Travis walks out the door of the kitchen half of the cabin, there is a thermometer nailed beside the door. In the late 1860's, when the movie takes place, thermometers like that were not available.
Factual error: The train's locomotive has a steel cab, an electric headlight, and other modern applications. Overall, it more closely resembles an early 20th century steam engine than that of the 1880's, when the movie supposedly takes place.
Factual error: When Brennan rides into town, behind the stage coach in the back street there is a pick up truck parked.