When Newly and Festus take off with the wagon filled with all the gold, the horses and wagon start moving too fast for all the weight in the wagon.
In a scene towards the end, BURLINGTON NORTHERN R.R. can be seen written across the locomotive tender. The BNRR was created in 1970 after a merger of four railroad lines (Great Northern, Northern Pacific, Seattle Portland & Spokane, and the Chicago Burlington & Quincy.