Runaway Train

The story follows the escape of two men from an Alaska prison, the efforts of a train dispatching office to safely stop the out-of-control train they are on, and the hunt by their warden to recapture them.Oscar "Manny" Manheim (Jon Voight) is a ruthless bank robber and hero to the convicts of Stonehaven Maximum Security Prison. After two previous escape attempts the doors to Manny's cell have been welded shut for three years. A court order compels Manny's nemesis, the vindictive Associate Warden Ranken (John P. Ryan), to release him back into the general prison population. Manny immediately sets his next escape plan into action.Buck (Eric Roberts) is another convict (convicted of statutory rape) who, due to his position in the prison's laundry room, is recruited to smuggle Manny out in a laundry trolley. Naive and unintelligent, Buck decides to escape with Manny, who doesn't care for company. After a freezing cross-country hike (involving a 300 ft drop into a river and subsequent swim) the two hop on board a train consisting of four locomotives at a remote Alaskan rail yard.Just as the train is set in motion, the elderly engineer suffers a heart attack. In attempting to stop the train and get off, the engineer does not close the throttle, instead pulling on the conductor's emergency brake lever, before collapsing off the still-moving train. Consequently, although the brakes apply, the locomotives overpower them, and the brake shoes burn off, making it now impossible to stop the train.Neither the two convicts nor the only railway worker left on the train, a locomotive hostler named Sara (Rebecca De Mornay), are aware of their situation (the convicts due to taking refuge inside the fourth car's toilet compartment, Sara due to being asleep in the second car).As the train accelerates, dispatcher Frank Barstow (Kyle T. Heffner) is alerted to the situation. Unaware of the failure of the brakes, Barstow authorises employees to allow the runaway out onto the main-line, arrogantly insisting that a computer-controlled signalling system of his creation will trigger a brake application on the locomotives. The last of the brake-shoes burn out and the dispatchers realise the severity of their situation, forcing them to keep the tracks clear.The runaway collides with the tail-end of a freight train that was in the act of moving out of its path. Learning that the train's excessive speed will most likely collapse an elderly trestle ahead, Barstow's superior orders him to derail it, believing that no one alive is on board.Upon doing so, the signal maintainer hears the whistle. Realising someone is indeed alive on the train, Barstow orders a reversal of the switch. The speeding train continues onwards towards the aging Seneca trestle, where emergency workers are gathering in expectation of a disaster.Warden Ranken concludes that his two escaped convicts are escaping by rail. Meanwhile, the two fugitives have found Sara on board when she climbs back to the fourth engine in the belief she'll be safer in a possible collision at the rear.Now aware the engineer must be dead, the three must get to the lead engine so they can press its emergency fuel cutoff switch. Sara informs them that they can't because the second locomotive is a streamlined F-unit with no forward catwalk. Its nose door, which would normally allow access to the lead engine, is jammed.
At her suggestion, they are able to slow the train by disconnecting the electrical bus link cables supplying commands to the two rear locomotives, shutting them down. Unintentionally, this slows the train enough that it is able to safely cross the Seneca trestle.The dispatchers divert the runaway onto a branch after determining it only five minutes away from a head-on collision with a passenger train. This is only a brief respite, as further ahead the branch negotiates a tight curve adjacent to a chemical plant. Even at its reduced speed, the runaway is likely to derail on this curve and trigger a major chemical spill.His hand forced by his superiors, Barstow agrees that they must switch the runaway onto a stub-ended siding and crash it, thus sending the three people on the train to almost certain death, rather than risk a catastrophic chemical explosion. Warden Ranken refuses to wait, coercing Barstow's assistance in chasing down the train by prison helicopter.Manny shows an increasingly violent streak, repeatedly asserting his dominance over Buck. He eventually forces Buck to attempt a suicidal scramble around the outside of the second engine's nose (Buck already having tried once and failed). Sara's intervention on Buck's behalf forces an armed face-off between the two convicts. Emotionally broken, all three slump into a fatalistic depression, only broken when Ranken's helicopter catches up with the train. Spurred on by the appearance of his arch-foe, and resolved not to return to prison, even if it means his own death, Manny makes a perilous leap to the lead engine. There, after a struggle with Ranken (who has successfully boarded by helicopter), he handcuffs Ranken inside the cab.To the music of the second movement of Vivaldi's Gloria in D (Et In Terra Pax), Manny then uncouples the first engine from the rest of the train, leaving Buck and Sara safely behind. He refuses to stop the lead engine despite Buck's screamed pleas. With Ranken his prisoner now, Manny climbs onto the roof of the lone engine in the freezing cold and blowing snow, his arms stretched out in a cruciform shape, ready to meet his end.After a series of cross-cuts of Buck and Manny's fellow inmates mourning in their cells at Stonehaven, the film fades to white and closes with an on-screen quote from William Shakespeare's Richard III:-"No beast so fierce but knows some touch of pity. But I know none, and therefore am no beast."

Question: Why did the dispatchers have to stop the train?
Answer: It was going to cause a major chemical spill; It was going to cause a major chemical spill