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To the discerning connoisseur of sci-fi adventure thrillers, “Source Code” is a model of crafty speculation. Not the best model, but better at least than its current competition. (Yeah, thanks for nothing, “The Adjustment Bureau.”) To the discerning connoisseur’s date, assuming he can manage to find one, “Source Code” is merely a fast-moving Jake Gyllenhaal vehicle. Still not the worst thing in the world, right?

A young man, played by Gyllenhaal, awakens abruptly on a Chicago-bound commuter train. He’s not sure how he got here, or why the pretty stranger across from him, played by Michelle Monaghan, is acting so familiar and calling him by someone else’s name. He thinks he’s an Air Force pilot, fresh from a mission in Afghanistan. But he’s dressed like a civilian, and getting looked at like he’s nuts. Feeling testy and a little freaked out, he repairs to the restroom, and the mirror shows him someone else’s face.

Then he learns that there’s a bomb on the train. Then he learns that his mission is to find the bomber, who has an even more destructive agenda for the rest of the day. One problem, aside from the general existential conundrum, is that he doesn’t learn these important things until after the train bomb already has exploded and killed him and everyone else on board. Which affords us an opportunity to point out that in this time of Congressional agony over budget balancing and fiscal prudence, someone really ought to have another long look at the problem of military inefficiency.

But anyway, now our pilot somehow is alive again, fastened a tad too securely into the isolation chamber of a dark and unfamiliar cockpit, getting orders videoed in from a prim but sympathetic liaison officer played by Vera Farmiga. Not the worst thing in the world, right? Nor exactly the best. It turns out that he’s guinea pig number one in a secret experimental project allowing him to relive and manipulate the last eight minutes of another man’s life. Allowing, that is, and demanding: He has to keep doing it, as many times as it takes, in order to prevent the greater and as yet still impending attack. On the plus side, there is still, and always, that pretty stranger who’s been acting so familiar. But what kind of a (borrowed) life can you make with someone in eight perpetually doomed minutes?

This is not time travel, exactly. It’s more like surfing the collective electrochemical resonance. Or something. It all — or, as much of it as time allows — will be explained by a staidly mad scientist played by Jeffrey Wright, who maintains his straight face while gently munching on the minimal scenery, like an earnest little termite. Meanwhile Farmiga dignifies her similarly belabored material, Monaghan stays dutifully cute and functional, and Gyllenhaal parses it all with just enough sincerity.

In “Source Code,” ideas matter more than special effects, which must explain why the effects look so cheap. Not that the ideas seem terribly expensive either. But for screenwriter Ben Ripley, who launched his career with “Species III,” this certainly counts as progress. The director is Duncan Jones, famously the son of David Bowie and the maker of the arty little sci-fi marvel “Moon,” who seems still to be enjoying himself and his surplus of audience goodwill. Honestly, Jones’ sophomore effort is a lot less horrible than its own trailer makes it seem. In fact, maybe Source Code’s only real problem is the internal pressure of making good on the many particulars of its own potential: As soon as you realize you’re dealing with an improbably Hitchcockian hybrid of “Quantum Leap” and “Groundhog Day” made by the spawn of Bowie, you do start expecting more.

Then again, it’s probably on account of some de facto Bowie gene-pool steez that the shock of this movie’s unequivocal clunkiness does wear off so quickly. That, and the narcotically comforting presence of Gyllenhaal, first established as a puzzle-movie dreamboat hero ten years ago in “Donnie Darko.” As it turns out, even the less discerning connoisseur may be pleased to discover that mind-bending genre geekery and popcorn-munching sentimentalism can exist in simultaneous parallel realities. Thus does “Source Code” make a useful contribution to its field.