Snicker all you like at this runaway freight-train movie, it is really only inspiring your wonder at how it turned out so damn entertaining. Frank (Denzel Washington) and Will (Chris Pine) take it upon themselves to stop a speeding engineer-less train hauling gallons of hazardous, flammable material. The result is one of the most satisfying high-concept action pictures of recent memory. Unstoppable's plot dispatches obvious and manipulative tension early (Children in peril? C'mon!) and generates thrills with a "try, try again" structure. Can't jump on to the speeding train by car? Try a helicopter or a second speeding train! Unstoppable has the tenacity not to slow down.