Editor's note: The following story has some spoilers about plot twists in "Unstoppable."

On a gray spring day in 2001, a 47-car CSX Transportation freight train got loose from Stanley Yard in Lake Township with nobody aboard its locomotive and traveled 66 miles to Kenton, Ohio, before a combined effort from railroad workers stopped it.

Today, Hollywood's take on that incident hits movie screens across the United States. It's predictably exaggerated and dramatized to make it more entertaining, but close enough to the real thing to support the "Inspired by True Events" announcement that flashes across the screen at its start.

Denzel Washington stars as a veteran railroad engineer whose successful pursuit of the runaway in his own locomotive slows it down just enough so that it doesn't derail in a populated area and release highly toxic cargo. His greenhorn conductor, played by Chris Pine, then jumps onto and rides a pickup truck pursuing the runaway's locomotive and leaps aboard to stop it.

That's not how the runaway was stopped 91/2 years ago in western Ohio, nor did the real incident start, as shown in the film, with a renegade engineer who couldn't be bothered to hook up his train's air-brake system.

But anyone who recalls the events of May 15, 2001, when CSX Engine 8888 rumbled off on its own, can't miss how the real-life drama was written into the script.

CSX officials probably won't be as impressed with the film's depiction of fictional Allegheny & West Virginia Railroad managers' willingness to risk a hazardous-materials catastrophe to avoid the up-front cost of derailing their wayward train in a remote area.

The company's first response was to try to derail its runaway, but the unmanned train ran through a track switch lined against it and knocked a portable derail off the rail without slowing down.

Only after those efforts failed was the crew of a Toledo-bound freight train waiting in a siding directed to uncouple the engines from their train and, after the runaway passed them, pursue it. In the movie, managers threaten to fire the Washington and Pine characters when they propose the same tactic.

According to a Federal Railroad Administration report, the real train was a yard-switching job whose engineer approached a misaligned track switch at the throat of CSX's Stanley Yard at a very slow speed that was still too fast for him to stop in time. So he climbed down from the engine to run and re-route the switch.

But in so doing, the report said, he failed to place his engine's brake-throttle selector in the braking position. So, when he shifted a control handle into full-power position, it was in full-throttle instead of full-brake. While he changed the switch, the train slowly pulled away before he could climb back aboard.

Locomotives have mechanical brakes as well as engine brakes, and the engineer had properly set the mechanical brake. Because that brake was set, a "dead-man" feature designed to stop the train if its engineer became incapacitated was disabled.

In the movie, the engineer also steps down from the locomotive to change a track switch, and while he's doing that, a control lever somehow moves by itself to apply full throttle power -- one of many elements likely to irk railroad-savvy viewers, although only a few materially affect the story line.

Movie dialogue soon brings up the "dead-man" feature, and a trainmaster played by Rosario Dawson explains that because the train's air brakes are not connected, it wouldn't work. That isn't exactly true, as the dead-man feature should also activate the locomotives' own brakes, but for simplicity's sake one could assume the movie engineer also applied the locomotive brakes.

Among the movie's first attempts to stop the runaway is the dispatch of another train's locomotives to pull out ahead of it, let it catch up, and then brake enough to allow a combat-veteran railroad employee dangling from a helicopter to drop aboard the unoccupied train.

But a sudden jolt sends the veteran crashing through a windshield, ending that effort, and an aborted attempt to derail the runaway at this point succeeds only at sending the slow-down engines careening off the track and wrecking in a huge, unrealistic fireball.

Although CSX may have considered sending engines out ahead of the real runaway as a last resort, this part of the movie is pure fiction.

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.

The real-life chase crew caught up to the runaway several miles before it reached Kenton, coupled onto its rear car, and braked it enough to get through sharp curves in town without derailing. Then a CSX trainmaster, Jon Hosfeld, was able to run alongside at a road crossing just south of Kenton, pull himself aboard Engine 8888, and stop it.

One way in which the movie and real life agree is the hazardous material carried in some of the runaway's cars.

Phenol, a chemical used in a wide variety of industrial processes, can cause skin, eye, or internal organ damage if touched or ingested, and is a toxic inhalation hazard if involved in a fire. While it does not readily ignite on its own, molten phenol easily ignites combustible materials, and burning phenol vapors may form explosive mixtures with air.

While the threat of fire was real had the CSX runaway jumped the tracks in Kenton -- or beyond -- and its two carloads of phenol had ruptured, "Unstoppable" amps up the threat by quadrupling the phenol car-count and placing the sharp curve atop a trestle next to a tank farm in a big city.

It also implies that a phenol incident would wipe out a large area, which is uncertain at best, although in a fire phenol could kill or severely injure bystanders.

Perhaps the most incredible aspect of "Unstoppable" is the speed with which news media portrayed in the film gain very detailed information about the incident and those involved as it unfolds.

For a railroad on the verge of a major disaster, the A&WV is amazingly cooperative about explaining its plans and providing employee names and photos to the media horde that chases the fictional runaway.

Television did cover the CSX train's "capture" live at the end of its journey, but it was months before an explanation of the incident's origins was made public, and the engineer whose mistakes were blamed was never officially identified, nor were details of any disciplinary action taken against him ever revealed.

Investigators recommended no sanctions against CSX for the incident after concluding it resulted from a combination of improbable events that could not have been foreseen.