In an early scene when Kitty, Doc and Matt are eating a meal in the diner, the sound of a steam locomotive is clearly heard over the dialog. It is clearly an audio clip of a steam locomotive pulling into a train station, complete with two separate train whistles and the sound of brakes being set. Apparently an audio mixing mistake, as no explanation is given and it is not addressed in the conversation of the three characters.
Matt and Chester are dragging an injured man into Dodge on a travois which would seem to be quite an unusual sight. But townspeople are seen walking the street and taking no notice at all.