(In theaters, December 2010) Railroad nerds better steel themselves, because Tony Scott’s latest thriller is a feature-length paean to American rolling steel, from lovely shots of moving locomotives to numerous behind-the-scenes explanations of how this stuff actually works. While it’s true that Unstoppable eventually becomes a competently-executed action thriller, it’s the film’s unusual focus on railroad mechanics that fascinate until the action truly starts. Loosely adapted from a true story (Search “CSX 8888” for the details), Unstoppable is about a runaway train and what needs to be done in order to bring it to a stop without causing massive damage. Denzel Washington is as good as usual as a grizzled engineer, Rosario Dawson does well in a role requiring no sex-appeal whatsoever and Chris Pine (stuck with a stock blue-collar character) solidifies his moderate credentials as an action hero. Meanwhile, Tony Scott deploys but does not indulge in the kind of hyperactive style he’s been using for a decade: his shots of rolling trains can become a bit too frantic to be properly appreciated, but he’s able to keep his worst excesses under control. Fittingly for its subject matter, the action scenes have the physical heft of colliding metal, the CGI gracefully bowing to physical effects. Structurally, the narrative is a predictable succession of failed attempts until our heroes step in to save the day: it’s a bit of a bother when some plans are so obviously underdeveloped that we know they’re doomed from the get-go. The “adapted from real events” presumably doesn’t extend to a few scenes milked for maximum suspense. Unstoppable is not a particularly refined film, but it delivers on its promise, and the result is a fine replacement for Runaway Train as the film most people will consider to be the definitive railroad movie.