Unstoppable is for fans of well executed, superbly crafted action film sequences, BUT not for those inclined to complex, ambiguous characters or enigmatic or surprising plot twists. Tony Scott, one of the masters of the action form, is at his cinematic best here with swooping cameras, heart stopping edits, in a rural gritty and real Pennsylvania railway locations (though I think Ohio doubled for it at times).
The charismatic cast is led by the great Denzel Washington, one of the most reliable leading men in all of movie-dom, in his new flavor of disillusioned, yet competent, capable 'old man' roles that he is beginning to play in his late fifties, and hunky Chris Pine, brimming with screen presence. They are joined by the lovely Rosario Dawson as a railway controller, (surprisingly credible) and veteran character actor Kevin Dunn as a sleazy railway executive.
The simple tale is based on an actual runaway train incident from about ten years ago. Due to human error, a train loaded with explosive toxic chemicals is hurtling towards a large population center. Two railway employees (Denzel, the grizzled veteran who's just been made redundant and Chris, first day on the job, the young new buck who's pushing old guys out in an evil downsizing), at risk of life and limb and in defiance of authorities, try to stop the hurtling train. That's all you have to know. There a subtext of the new depression, the fading railroad and a changing (for the worse) America, but it's not that heavy. Just sit back and enjoy the train action and the heroics.
The film is tasteful throughout and is surprisingly wholesome, with very little profanity, no sex (well, Denzel's daughters are Hooters Girls), and has snappy and not too cliched dialogue. It avoids the trap of using trendy pop culture references and tropes, giving the film a timeless quality. It's a great choice to enjoy with the whole family, though I would imagine the bigger fans of the film would be boys who have just grown out of their Bob the Builder DVDs. If you like railroads and trains, you'll be in heaven.