Once Unstoppable does the obvious and actually, you know, involves its main characters in its story, it’s a solid action thriller. The problem is it takes an hour for this to happen, and by then it’s too little, too late.

This is a shame given that it is the fifth collaboration between Denzel Washington and director Tony Scott (Man On Fire). With Washington’s notable screen presence and Scott’s trademark hyperkinetic style, we have every right to expect more. Washington plays Frank, a veteran train engineer working on the Pennsylvania railroad freight lines. Today he is training Will (Chris Pine of Star Trek), a young conductor with family issues. The two men engage in typical guy talk and waste a lot of time, as Mark Bomback’s script keeps them apart from the action with nothing interesting to do or say.

Meanwhile – 200 miles away from the big-movie-star main characters – dramatic things happen. Two idiot yard workers (Ethan Suplee and T.J. Miller) are told to move the 777, a 39-car, half-mile-long, toxic-chemical-carrying train because some school kids are coming to visit. Should be simple enough, but when one of them gets off to take a short cut, he accidentally leaves the train in full throttle and get can’t get back on. Oops. So now the unmanned train is speeding toward a train full of school kids and a big curve in an industrial city, where it will likely derail and destroy everything in sight.

Back to the school kids. As the 777 and the train with the kids speed toward one another, Scott has a chance to create a scene of genuine tension and suspense. Instead the scene ends far too quickly, and feels like a missed opportunity to get the audience emotionally invested in the danger the runaway train presents. This is especially worth noting because all the action scenes are underwhelming except for the finale, which is exhilarating.

Expectedly, best efforts are made to stop the train. Yardmaster Connie (Rosario Dawson, playing the token tough female character in this man’s world) disagrees with every decision a railroad exec named Galvin (Kevin Dunn) makes, and I’ll let you guess if the blue-collar worker or corporate bigwig ends up being right.

Eventually 28-year veteran Frank decides to put his vast experience to use, and once he does, the movie gets better. Too bad it takes an hour for this to happen.

Why Unstoppable would keep Frank and Will away from the main storyline for so long is anyone’s guess, but because it does – and the rest of the movie is filled with clichés and poorly edited action – this is one train you’ll want to miss.

UNSTOPPABLE (2) Directed by Tony Scott • Starring Denzel Washington, Chris Pine, Rosario Dawson • Rated PG-13. 98 min. At Century Cinemas Del Monte, Maya Cinemas and Northridge Cinemas.