Continuity mistake: When the Russian Major is talking to the other lower ranking soldier just outside the train, in one particular shot the soldier is looking directly at the Major. Then in the following shot he is looking down at his feet, and lifts his head up twice to look at the Major again. (00:04:15)
Continuity mistake: When the Major and General are on top of the train just before they jump from one train to the other, the Major and General walk across the top and they pass one, maybe both, of the hijackers. When it cuts to another view, the hijackers are passing the Major and General again. (00:11:30)
Continuity mistake: When the hijackers are setting the nuclear bomb, they drill a device to the face of the bomb, and on the right of the screen there are wires sticking out of the little silver box. In the following shot one of the hijackers opens the little silver box and pulls the wires out again. (00:12:10)
Continuity mistake: Just before the two trains crash, there are 4 poles along the track and not far apart, then when the camera cuts to a wider shot, there are fewer poles and at a much greater distance from one another. (00:14:20)
Continuity mistake: When Julia is first seen she is explaining the satellite images to a guy, and in one particular shot she holds the photograph near the bottom of it. Then in the following shot of the photo, her hand has moved up to the top of the photo. (00:18:25)
Continuity mistake: When Julia is giving a brief to the people in the room about terrorists and such, Tom interrupts and walks over to the screen. In this shot Julia is raising her hand/hands and pointing at him, yet in the following shot her hands have not moved from her side only her head has moved to the mic. (00:23:35)
Continuity mistake: When Tom and Julia are in Julia's office, Tom sits down while Julia is on the phone and begins to read the small card from the flowers. In one shot Tom's three/four fingers are on the back of the card, then in the following shot he is holding the card at the edge with just his fingertips on the card. (00:26:55)
Other mistake: Early in the film, LTC Tom Devoe takes a fax of the alleged missile train departure orders off the machine, and starts reading it as he walks to Dr. Julia Kelley's office, taking a moment or so to reach the office. After talking with Dr. Kelley for a moment, he still scans the list looking over her shoulder. After he walks away, Dr. Kelley reads aloud Kordurov as the second name on the list. Wouldn't Devoe have recognized the name as he scanned the list before he gave it to Dr. Kelley? (00:28:55 - 00:29:45)
Continuity mistake: When Tom and Julia are on the way to Vienna Tom changes seats to sit opposite Julia, and he puts his mug down with the mug's handle facing towards the plane's window. In the following shot the mug has turned around its handle is now facing Julia. (00:33:30)
Factual error: The German text on the screen in Vienna has many small spelling errors. 1.) Under the sign of printing you read the English "Quantity" and the German "Betrag" (Amount) in the same invoice 2.) Under the search bar you first read the wrong word "Schen", one minute later the right "Suchen" (Searching) (00:44:05)
Continuity mistake: Just after they get the information from the guy's computer, Tom's friend picks them up. His window is up as he pulls up to pick Tom and Julia up, yet the next time we see it a second later it is down then it is back up in all other shots. (00:45:00)
Continuity mistake: When Tom's friend gets shot and the other guy starts to shoot at the windshield, the bullet holes change between shots. (00:46:35)
Continuity mistake: Just after George Clooney's friend has been killed, he roars off in his car, banging the BMWs. A bit of plastic each side of the bumper falls open, nearly coming off. A few shots later the car's driving towards the camera and they're both back in place. (00:46:50)
Continuity mistake: During the Vienna chase, the guys in the black cars are behind a red van, and the red van passes the side street where Tom pulled into, yet from Tom's POV it's passing again. (00:47:50)
Continuity mistake: When Tom and Julia get out the Mercedes before it explodes, Tom shuts the drivers door after getting out, yet in the following shot it is open. (00:51:00)
Continuity mistake: Just after the explosion in the square, we see a shot of the Mercedes' door, and it's still bright silver. In the shot immediately afterwards of George Clooney and Nicole Kidman getting to their feet, it's charred black. (00:51:10)
Continuity mistake: When Julia gets email on her laptop in a Vienna hotel room, Tom walks up and looks at it. In this shot Julia taps quite hard on the keyboard then take her hands away from it, yet in the following shot her hands are still on the keyboard. (00:53:50)
Factual error: "Lieutenant" Beach is actually wearing the rank of a Warrant Officer 4 (WO4) on his collar and head gear (beret). (01:00:02)
Continuity mistake: When the Colonel, who is carrying the nukes in the truck, has to stop at a checkpoint, he shoots two guys out at the front of the truck beyond two round small containers, but they suddenly disappear in all the following shots. (01:05:15)
Continuity mistake: When George Clooney is waiting for permission to enter Russian airspace in the helicopter, you can see all three choppers hover about 2 meters above the ground, but in following scenes, they are at much greater heights. (01:06:50)
Answer: The two train engines colliding caused the explosions, all the other cars derailed. All the warheads were carefully packed and disarmed.