Corrected entry: Captain Garza is a Navy Captain, and an aide to the Admiral in Under Siege I, which takes place some 3 years earlier. In U/SII, he is still a Captain, and still an aide to the Admiral (highly unlikely that his tour of duty would last 3 years), while Casey Rybeck has gone from being an enlisted E-7 to becoming a commissioned officer, and promoted at least one pay grade.
Corrected entry: When the two trains crash into each other at the end if you look closely you will see that Ryback's train is derailed before it actually hits, causing the other train to hit it on the side, rather than the front.
Corrected entry: In the scene were Ryback jumps from the rock back onto the train, he lands on his feet and doesn't fall back. In actuality, with the train traveling even just 30-40 mph, and facing the way he was, Ryback would be slammed on his back instantaneously when he his feet first touched the train. Ryback would have to be running along on the rocks at approximately the same speed of the train before he jumped, in order to land on the train and keep his feet.
Corrected entry: In the same scene where Penn's henchmen find out that Ryback is on top of the front carriage, the men in that carriage start firing at him. Under fire from the bad guys, Ryback pulls out a machine gun and fires back. Where the hell does Ryback get this gun from? Before he approaches the carriage you clearly see him carrying no other weapon besides his pistol. He has killed two bad guys before this and may have taken their weapons, but you never see the machine gun on him when he is under fire. Magically he pulls one out and fires back.
Corrected entry: How does a portable radar device inside a metal moving train in the mountains detect an F-117 stealth fighter, which has a radar cross section the size of a bumble-bee?
Corrected entry: When Ryback enters his message about the train being hijacked into his PDA he FAXes it to the Mile High Cafe. However, listed immediately before the Mile High Cafe on the PDA's phone list is Seal TAC. It's implied early in the movie that Ryback is now a Lieutenant in the SEALs. Wouldn't it make more sense to send a message of a hijacked train to the SEALs instead of a restaurant?