Plot hole: Had one or more locomotives coupled onto the real runaway's front engine, or even just been pushed by it, anyone aboard the "rescue" engine could have just walked to the unoccupied ones and shut them down - no copters or fireballs required.
Factual error: In the yard scene when Dewey tries to change the switch, the throttle lever slips from idle to full power. This would not have been possible. Throttle levers are notched, and require significant force to move.
Other mistake: In the scene immediately after the locomotives that were trying to slow 777 get derailed and blow up, the next scene immediately shows Colson in the cab of his train exclaiming about the explosion which he sees just over the tree tops. Impossible. Colson's train is still miles away on the head on collision course with 777, and Colson could not possibly see this explosion, let alone as if it was just around the bend.
Continuity mistake: After the loco connects to the back of the train, a couple of scenes show the engine with the air hoses connected, and some do not. These hoses can only be connected from ground level.
Continuity mistake: As the train goes around the curve, Barnes is running across the tops of the tank cars. In one shot he's on the last car before the pipe car, but when they switch back to him again he's still running and there's another tank car in front of him.
Continuity mistake: In the scene where the train hits the horse trailer, it knocks its left side light out. However each scene after that showing the train it has its right side light broken.
Continuity mistake: After the double train fails to slow train 777 and gets switched to another section of track, in the control room, you see the train has already partly gone around a bend on the TV screen behind the bearded character, then cuts to the TV report footage which shows the train continuing on for a few seconds, though when the scene cuts back to the train, it is only just beginning go around the same bend that it had already partly travelled. (00:45:20)
Continuity mistake: The horse trailer is shown sitting across the track, but when they are unloading the horse the back of the trailer is facing along the track.
Continuity mistake: In the scene when Train 777 is coming straight at the passenger train with the kids, the train is coming straight at them (just a single track). But a few shots later, a rip track leading to a siding comes out of nowhere without being seen. (00:23:05)
Suggested correction: The view at the single track is obviously not from the other train's perspective.
Factual error: In the yard when the air hoses are discovered to be not connected, the purpose of the connected hoses is to release the brakes, not apply them. With the hoses disconnected the brakes on all the cars are automatically applied.
Suggested correction: I'm a locomotive engineer. The air hoses have to be hooked up to apply and release the brakes. They are not necessarily applied if the hoses are disconnected.
They will apply if the gladhands disconnect en route.
Factual error: Towards the end, when the red pickup is alongside 777 with Colson on the back, the camera shows the speedo of the truck, and the needle going over 60 MPH. This speedo shot is of a 1967 Shelby Mustang GT 500, not a Ford Super Duty. As an aside, this shot is taken from "Gone in 60 Seconds", with Nicholas Cage.
Factual error: In the scene where they try to slow the train with 2 engines and lower an engineer aboard, at the end the 2 engines derail as they go onto a siding and explode. Engines like these would never explode in real life, and none have ever done so in any derailment in history. They only contain diesel fuel which is very difficult to ignite, only other cars with flammable materials ever explode in real derailments. In the scene they do not strike anything else with explosive potential, and the explosion is not necessary for the plot. The engineer aboard could likely have died still just from the speed of the derailment.
Other mistake: In the scene when Will finally stops the train, his phone beeps letting him know he has a missed call. He looks at his phone and sees the photo he presumably has associated with his wife Darcy. Later on, during the press conference scene, right after the first part of the dialog between Will and Frank about "corporate", there is a shot of Darcy at the press conference. This exact same shot was the photo used in Will's cell-phone earlier on. (01:30:20 - 01:31:40)
Factual error: In several scenes PA State Police Troopers are shown wearing metal badges on their shirts or jackets. PA troopers do not wear shirt badges. Their hat is considered their badge of authority.
Continuity mistake: In the big finale where Ned is racing alongside the train in his truck and picks up Colson, they have said that the 777 is at 75 mph and gaining speed toward 80. Yet the view of Ned's speedometer shows him just getting to 70 mph while he is passing the train. To be passing the train he would have to have been in the 90-100 mph range.
Continuity mistake: When Frank asks for their work order, Will says they are supposed to pick up 25 cars. After picking up the 25 cars, Frank notices that the train is too long and asks for their work order again. This time, Will says they were supposed to pick up 20 cars.
Plot hole: According to the channel 8 live report "the railway company is still not commenting." Yet they knew what happened to make 777 unmanned, that Dewey was the driver, his age, that he would face disciplinary action, that it was Ryan scott attempting to board, his age, that he was an ex marine, that he'd just came back from Afghanistan, that Judd Stewart was driving the front loco and his age, the names of Frank and Will and what they were attempting to do. That's an awful lot of accurate, detailed information when the company is apparently not commenting.
Continuity mistake: When Ned, Dewey, and Gilleece are arguing at the mile post marker, Ned's cell phone constantly disappears, reappears, and switches ears and hands. (00:21:15)
Factual error: When Connie asks Frank how much power 1206 has, he responds, "5,000 horses." 1206 is an EMD SD40-2 that has a power output of 3,000 hp. Furthermore, when asking about the power output of a locomotive, it is typically given as HPT (Horsepower per Ton) and not as the total horsepower of the locomotive. (00:47:50)
Continuity mistake: Colson is blasted in the face with grain when the train car carrying the grain explodes, and his hair is blown about. When he goes back into the cockpit of the locomotive, there is no grain on him and his hair is neat.
Suggested correction: Not necessarily. Some engines may not have a rear cab access (like Frank/Will's engine had). And even if the rescue engine did have a rear cab access 777's engine only had a side access stair which at the speed it was going is more difficult to climb over from the engine in front of it.
Actually 777's catwalk goes across the front, from side stair to side stair, but someone would have to leap over a rail or a chain to get onto it from the other engine. Why would there be stairs on the right side unless there was a catwalk to get to the door on the left side?