Continuity: After Manny's fingers get crunched between the cars, blood sprays on his face. In the next couple of scenes there is hardly any there. Also, when the prison warden get sprayed with the fire extinquisher he is cleaned up in the following shots.

Factual error: The train consists of four locomotives, but some close ups show wheels of freight cars.

Deliberate "mistake": The entire plot wouldn't exist without this one, but just before the engineer stumbles out the door and falls off, he pulls the big red lever on the left side of the cab. In the real world this puts the air brake system into its emergency mode. Among other things, this mode trips a solenoid which causes the engine to return to idle, and the electrical system to not put out power. Neither the Diesel engine nor the electrical system will respond to control inputs until/unless the air system is reset.