The man whose appearance Rusty is describing changes position between shots as Rusty talks to Britt.
After Britt peeks in the bedroom and sees Tom is dead, he stands in the doorway and places a hand on the frame, which he then removes as he talks to Clint. It then cuts to a close-up and Britt's hand is back on the frame.
The narration says Lincoln said "with malice toward none, with charity towards all" at Gettysburg. The quote is from his second inaugural address delivered at the capitol.
The film shows the railroad being completed into Santa Fe, NM. The AT&SF railroad never went to Santa Fe (despite the name). Although the main line did not reach Santa Fe, a branch line was constructed to stop there.
In the first few scenes, modern 3 phase electric power lines are visible. That kind of power had not been invented then.
A locomotive is shown with the marking "Denver Rio Grande" on its side. It should have been "Denver & Rio Grande"
The interior of the pay car is far too spacious to fit inside a railroad car.
The locomotive "C.K. Holliday" has the number 1 on its front number plate, but 5 can be seen on the side of its dome.
The story is set post-civil war, but all the major characters carry Colt Peacemakers with 4 3/4 inch barrels. This model was developed for the US Army in 1873. Civilian sales started in 1875, and the 4-3/4 barrel length wasn't available until 1877.
The train is equipped with knuckle couplers and Westinghouse air brakes, neither of which existed at the time.