Chance and the bartender draw their guns on each other after a shoot out, both pull their triggers at the same time and hear clicks realizing that both of their guns are empty. In reality the slides on their guns would have locked back indicating that the gun was empty. Also, being proficient in small arms they would have most likely been able to tell by the diminished weight of their guns that they were empty.
When Christopher parachutes out of the back of the train, he is shown to be moving in the opposite direction of the train and slide back towards the tunnel entrance. The parachute would have slowed him down very quickly, but not instantly taken him from 200 mph in one direction to 10 mph in the other.
Stephanie Dobbs says she ran the design team for the monorail.
However, the vehicle changes from being a regular bullet train to being a monorail. For example all but one exterior CGI shots show it to be a normal train, however all the interior scenes show it to be a monorail (the brake disc bursting through the centre of the car for example)