Christina's hair is styled differently in the last scene in the train and the one immediately after when she and Colter have left the train and are walking together in Chicago. In the train her hair's tips are clearly pointing outwards and in the following scene they are just laying on her back.
The mission involves Stevens trying to find information about a dirty bomb attack on Chicago. A "dirty bomb" is simply a regular bomb with radioactive material packed around it so that the explosion will spread harmful radiation over the blast zone. It is not a nuclear bomb, and while it would expose those in the area to potentially lethal levels of radiation it would not "kill millions" as stated in the movie.
Colter Stevens communicates with Goodwin via text displayed on a computer screen, but when Stevens (seen sitting in the imaginary cockpit, speaking out loud) asks her, "Are you married?" she responds as if someone is speaking to her and she didn't hear him at first by saying "Hmm? No, I'm divorced."
The college kid flips open Frost's wallet and the driver's license is visible. Later when Colter Stevens opens Frost's wallet, Stevens has to slide the license out of a pocket in the wallet before it is visible.
When Goodwin pulls up Frost's driver license information on her screen, the address, SSN, height, weight, DL # and eye color are different from the ones Stevens sees on his actual license on the train.
Just before Stevens confronts the bomber, when approaching the white van in the parking lot, there is a huge sculpture in the background. This is "Man" by Alexander Calder on Ile Sainte-Hélène in Montreal.
The Glenbrook train stop mentioned in this film exists only in the north/northwest suburbs of the City of Chicago. Yet in every last-minute, prior-to-the-explosion shot where the passenger train is about to blow up, the train is shown as heading northbound into downtown from the south. This is impossible given the Glenbrook stop.
It is stated multiple times throughout the movie that the train's destination is Chicago's "Union Station" located in the base of the WiIllis (Sears) Tower. Yet near the end of the movie, the train is seen pulling into Chicago's "Millennium Station", located about 1.2 miles East of "Union Station".
Captain Goodwin has five service ribbons: a Bronze Star, an Air Medal, a Joint Service Achievement Medal, Kuwait Liberation Medal (awarded by Saudi Arabia), and a Kuwait Liberation Medal (awarded by Kuwait). However, she is missing her Basic Training ribbon.
When Colter Stevens is on the train and makes the cell phone call to Nellis Air Force Base, the voice on the other end says, "Post Operator." If he was calling an Air Force base, he would be connected to the "Base Operator." Only Army facilities are called "Posts."
Captain Goodwin's uniform is incorrect. Blue name tags are not worn on the Air Force service coat. (Blue name tags are only for the shirt, whereas silver name tags go on the service coat). Also, her U.S. insignias are not properly placed on the lapel.
When security personnel are called in, US Army Military Police show-up. Nellis Air Force Base, like all Air Force Bases, is protected by US Air Force Security Forces personnel. Contractors are sometimes used to provide minor assistance such as checking identification at gates, but MPs would not be stationed on an Air Force Base.
In Cpt. Stevens flashback he radios in that "do you copy that we are taking a lot of RPG fire..." and the file shows large amounts of AA fire with tracers. Flying at dusk/night the visualization of RPG would be the "blink of light" at the launch site and nothing else as the rocket is virtually invisible day or night leaving nearly no smoke trail at all. An RPG hit, as insinuated, on a UH-60 a UH-60 as pictured, would instantly bring down the aircraft from blast damage and destruction of the cabin/flight system.
The license plate on the white van has the configuration of numbers and letters that California has, not Illinois. Illinois plates (including in 2011) generally have three figures, then a space, then four figures. California plates have a number, three letters, and three numbers, all in a row, as the van's does.
The conductor always asks Colter for his ticket, but never asks Christina for hers. On Chicago commuter trains, conductors collect tickets as passengers get on; Colter must have gotten on after Christina.
At approximately the one hour mark, when Frost shoots Colter and Christina, the wide shot of the scene as he drives the van away shows a pool of blood by her head on the ground. The pool of blood is gone in the closeup a few moments later.
When Stevens inspects Derek Frost's wallet after he throws it back on the train, the drivers license shows Frost's birth date is 02/01/82. However, when Goodwin checks the license after Stevens identifies him as the bomber, it lists his birth date as 02/21/83.
When Captain Coulter Stevens has his physical body shown the first time, the EKG electrodes are in the wrong position (white should be on the right shoulder, black should be on the left shoulder and green should be on the lower right limb).