Other mistake: There's a minor technical error in the portrayal of the telegraph equipment at the train station. When a message was coming in for the stationmaster the repeater relay, on the left, was shown clicking away. The telegraph sounder to the right wasn't moving. Both should have been in use as the repeater relay would have been fairly quiet while the sounder would have created the loud audible clicks. Repeater relays with fresh sets of batteries permitted the telegraph signal to travel greater distances by regenerating the Morse code signal at each telegraph office. The sounder made it much more audible. An office at the very end of a telegraph line would only have a sounder.
Other mistake: When Kane comes to warn Ms Ramirez that Frank Miller is in town, Kane puts his black hat in a chair by the door. When he approaches Ms Ramirez, he has the hat in his left hand.