"Unstoppable" is pure formula, sheer popcorn, but also a fair amount of fun if one can get past the more rudimentary clichés found within director Tony Scott's design. For the filmmaker, whose signature swirling camerawork and epileptic editing are usually a great deal more effective than Michael Bay's tornadoes of disorganized chaos, this is his second straight train-in-peril thriller (following 2009's inferior remake "The Taking of Pelham 1 2 3"). Straightforward and incisive, "Unstoppable" sheds most of its extraneous meat and gets right down to business. The characters are types more than fleshed-out human beings—attempts to add personal conflicts for the two heroic leads come off as strictly perfunctory in a screenplay written by Mark Bomback (2008's "Deception")—but there's no denying how well director Scott is able to keep the plot moving and the tension thick.

It's the first day on the job for novice Pennsylvania train conductor Will Colson (Chris Pine), but his tumultuous pairing with veteran engineer Frank Barnes (Denzel Washington) is small potatoes in comparison to what's headed their way. An unmanned half-mile-long train with disconnected air brakes is zooming ever faster toward the town of Stanton, where a sharp curve could send it barreling off the track. What's worse, the locomotive is carrying thousands of gallons of gasoline and toxic chemicals, enough to wipe out anything within close proximity if it crashes. "We're talking about a missile the size of the Chrysler Building" is how railway controller Connie Hooper (Rosario Dawson) none too reassuringly describes the situation. When a rescue from the air fails, a nearby Will and Frank take it upon themselves to try and avert disaster.

An action film about a passenger-free runaway train doesn't sound terribly exciting since there's only so much that can be done with the sight of a choo-choo roaring down the tracks, but director Tony Scott, along with cinematographer Ben Seresin (2009's "Transformers: Revenge of the Fallen"), shoot the heck out of it. The camera literally never stops swooping and gliding below, above and around its subjects, while the cut-heavy editing mimics the loss of control at its story's center. Nevertheless, there is a sturdy, well-conceived command of Scott's mise en scene, and it goes a long way in retaining steady involvement and a gradually escalating intensity to the proceedings. A train filled with kids on a field trip are the first to be endangered, but this quandary is quickly resolved. So, too, is a car accident across the tracks involving a horse trailer—the shot of a spooked equine unknowingly in the train's imminent path is striking—which leaves the majority of time dedicated to the actual race-against-time rescue attempt.

The actors are called upon for more technically accurate duties than emotional. Denzel Washington (2010's "The Book of Eli") and Chris Pine (2009's "Star Trek") are in solid form as engineer Frank Barnes and conductor Will Colson, but their roles are mostly limited to sitting in the head car of a train and alternately sparring with each other and reacting to what's surrounding them. Both are facing personal issues, but these are decidedly hamstrung filler. Frank is a widower having trouble connecting with his teenage daughters (Elizabeth Mathis, Meagan Tandy) and facing an age-discriminatory forced retirement, while Will, who acted rashly after suspecting wife Darcy (Jessy Schram) of an affair, has just learned that his restraining order has been extended. In one clumsily written scene where Will opens up to Frank about his troubled family life, the would-be drama turns unintentionally funny when it is inadvertently suggested that Darcy has been carrying on an incestuous relationship with her sister! Stuck back at the railway control headquarters, Rosario Dawson (2008's "Seven Pounds") transcends her slim, unrewarding role as Connie Hooper and makes the viewer wish her character were better developed and, perhaps, in a different film altogether. When Dawson is on the screen, she is so immensely watchable that everyone else ceases to exist.

Overcast and atmospheric, "Unstoppable" carries a portentous aesthetic matched by its working-class Pennsylvania milieu. The climax, where Will and Frank make a life-threatening last-ditch effort to slow the train down before they reach Stanton, ratchets the suspense to giddily satisfying levels. What isn't so pleasing is the irksome convention director Tony Scott insists on returning to as side characters and onlookers watch with gaped mouths and pumping fists the events unfolding on television. This just comes off as cloying and artificial, a ploy to manipulate that doesn't work for a second. When cut down to its essentials, though, "Unstoppable" is a skillful, no-fuss action-thriller with a sharp eye and ear that fortunately reconciles its lacking heart.