Runaway Train (1985) on Netflix

Manny is the "boss" of the convicts in an Alaskan high security prison. Renken, the heartless prison's administrator wants to kill him, so Manny escapes with the help of another young prisoner, Buck, who follows him. The two fugitives manage to get to a rail depot and get onboard a train. The problem is, the engineer has died and the the train is totally out of control, and nothing can stop it. So, leaving the prison, Manny and Buck find themselves aboard something that is both their freedom and their death...