Factual error: Near the end of the movie, as the money train is approaching the passenger train, the motorman is communicating on the microphone with dispatch. If you notice, as he is talking, his hand is NOT on the throttle. On the trains in the NYC subway system if the throttle is not depressed the train will stop.
Factual error: In many of the subway scenes the trains carry only three cars. There are no subway trains in New York that carry just three cars. The least amount of cars for a subway train is four, and that number only applies to the shuttle trains. The other lines in the subway carry between eight and eleven cars.
Factual error: When Charlie suggests "bleeding the brakes" on the train, or letting the air out so the train couldn't be tripped or stopped, that would have the opposite effect. Letting the air out of the brakes on a subway train applies the brakes. The air pressure keeps the brakes off. Eliminating that pressure would cause them to instantly clamp down. It's one of several safety redundancies. (01:24:10)
Factual error: After John and Charlie jump off the money train, it reverses and derails onto its side, and rolls for some distance in the tunnel, knocking down all support columns in its path. Those columns are not as flimsy as the film suggests, and would actually have sliced the train and/or cause it to buckle, as had happened with a similarly derailed train near the 14th Street-Union Square station in 1991.