Having played with fighter jets, race cars, submarines and subway trains in “Top Gun,” “Days of Thunder,” “Crimson Tide” and “The Taking of Pelham 1 2 3,” director Tony Scott still isn’t done hurling around huge deadly vehicles. In Scott’s new action thriller, Denzel Washington, Chris Pine and Rosario Dawson contend with a combustible runaway freight train in rust-belt Pennsylvania.

It’s hard to imagine a person coming out of “Unstoppable” feeling disappointed, because then you’d also have to imagine what that person possibly could have expected going in. Scott and writer Mark Bomback’s formula is basically standard elementary school word problem by way of prime-time truck commercial, and it’s sort of tickling to see how well it works.

The characters are, of course, perfunctory. Washington’s the railyard veteran, a widower whose two daughters (Elizabeth Mathis and Meagan Tandy) both are working their way through college, at Hooters. (That is, they work at Hooters. I didn’t catch where they go to college.) Pine’s the upstart, a callow conductor with dubious family-legacy union connections and a restraining order against him from his own wife (Jessy Schram). Dawson is their yardmaster, evidently comfortable in a job that requires ritual slatherings of testosterone, and collected enough to say, “This kind of thing happens,” when a full-throttled train gets loose with no one aboard, and heads through the heartland straight for a populous city.

So never mind about characters; just see them as types, suitably enlivened by the actors’ personalities. Actually, Pine doesn’t much seem to have a personality here, but that might help. (He wouldn’t want to upstage his own Captain Kirk.) Dawson has a knack for emotionalizing without overdoing it. And, well, Denzel is Denzel.

As problem-solving proceeds, there will be tension between the fellas. And with rising stakes, there will be bonding. They decide to take their own locomotive after the runaway, and Scott knows when it’s time to peel out, zoom in, suit up, throw down, and power on through.

Scott’s films tend to favor a certain manner of editing which seems antagonistic to coherence. But in this case, it doesn’t matter. At any given moment, figuring out what’s going on could not be easier. Has the train been stopped? No? OK, you’re caught up.

He’s also cordial enough to provide a quick, need-to-know survey of social-strata fault lines, ranging from the tubby lazy guy who’s responsible for the crisis (Ethan Suplee) to the faraway fatcat boss who doesn’t listen (Kevin Dunn). Plus the requisite obstacles: a train full of schoolkids approaching from the other direction, a horse trailer on the tracks, and the mixed blessing of real-time Fox News coverage of our flawed blue-collar family men risking life and limb to rescue their community from impending catastrophe.

There is joy in the realization of this, as if Scott once was a kid with a model train who thought, “It would be SO AWESOME to smash and blow this stuff up,” and at long last is living that dream and telling himself and everyone around him, “Yes, this is, as I expected, SO AWESOME.”

Granted, men of Scott’s generation, particularly Englishmen, may not seem normally inclined to say such things. Nor are they normally inclined to ventriloquize Middle America. But has that stopped him?