Character mistake: After Kimble jumps from the drain pipe over the waterfalls, the scene goes to Gerard standing in the pipe telling his crew to leave, then they all leave without picking up Gerard's gun that Kimble threw down next to him.
Revealing mistake: Just after the opening murder scene, there's a shot of a Chicago Police van responding with blue lights flashing. If you look closely at the roof lights between the beacon on the right side of the roof you can see a sign "FILM2" stuck to the bar. (00:01:55)
Factual error: In the train crash scene there are many mistakes. 2 locos are pulling a hand full of cars, a small switcher loco would actually have been used. Oil journal bearings that haven't been used for decades. A flat car carrying logs, but there is no logging in the Chicagoland area. The second loco for some reason derails. In reality the train would have just pushed the bus a few hundred feet with no derailment. The shed explodes. The 200 ton loco just slides along the soft ground.
Continuity mistake: When Kimble is on the moving train, Sykes mysteriously appears from a door when he wasn't there before. (02:00:00)
Answer: He's the one whose house they storm (he gets shot).