Factual error: When the porter first gets ready to shoot at the terrorists (after Ryback falls off the train) he goes through a series of verbal instructions to remind himself what to do. The very first thing he says is "safety off". The problem is that the gun he is using is a Glock pistol. Glocks use a device called a "safe-action trigger" but they don't have a manual safety that you turn on and off.
Continuity mistake: After the train comes to a complete and lurching stop, the porter is shown being thrown forward into the bad guys as a lot of baggage falls all over the place. In the final fight scene as Ryback is entering the dining car, all the tables have all their place settings perfectly intact.
Plot hole: Now why the heck is one of the stealth fighters anywhere near the train? Stealth fighters use advanced targeting and do not need to be anywhere near their target, yet in the movie the one fighter is so close to the train when it gets blown up that it looks like it's on a collision course.