Backtracking: "Source Code"

And you thought you had a lousy commute. In Source Code, Jake Gyllenhaal wakes up on a train bound for Chicago with no idea of how he got here or who his fellow passengers might be, save that they're variously tetchy or klutzy, abusing railway employees and spilling coffee on our hero's loafers without deigning to offer so much as a single word in apology. Retreating to the bathroom in order to compose his fevered thoughts, he finds the face of a complete stranger looking back at him from the mirror; and just as the pretty girl he's travelling with utters the supposedly reassuring words "everything is going to be all right", a bomb tears through the carriage, killing everyone on board. What's more, Gyllenhaal will relive this experience a further six or seven times in the course of the movie, expiring each time. It's better than going by First Capital Connect, but perhaps not by much.

Director Duncan Jones' 2008 debut Moon was a two-man show, a showcase for both a newbie filmmaker and his leading man Sam Rockwell. This follow-up is equally contained - for two-thirds of Source Code's duration, we're stuck on the train alongside Gyllenhaal - yet somehow more expansive. It could certainly be described as a post-Matrix (or post-Avatar) movie, in that the hero is caught in a kind of limbo for much of it, present only as a series of thought impulses: Jake's Captain Colter Stevens is, in fact, wired up inside a hub as part of a military program that allows combatants to be beamed into the bodies of the deceased in an attempt to to prevent certain atrocities. He has exactly eight minutes (a technological limitation) to figure out who planted the bomb on the train.

On his first pass, he has no idea what's about to happen; on the second, he locates the explosive device, but can't disarm it; on the third, which plays like a romantic interlude of sorts, he tries to get the pretty girl (Michelle Monaghan) off the train, only to himself end up back on the tracks. At once, Source Code appears to be channeling Groundhog Day, Quantum Leap (Jones recognises as much, by casting that show's leading man Scott Bakula on the other end of a telephone as the hero's father) and Before Sunrise. It is, also, an opportunity for an upwardly mobile director to refine their craft. Each eight-minute sequence becomes, in effect, a separate take; like his hero, Jones has to work out how to get the best from the limited time available to him. As with Bill Murray's weatherman in Groundhog Day (or the players of any console game), the process of rebirth gives Stevens the chance to learn from his mistakes - and it's sort of telling the Captain should have been beamed into the body of an American history teacher: the bombs in Source Code arguably wouldn't have the impact they do outside of our present climate of fear.

Yet, for all this, the film isn't quite as satisfying as its admitted sources. The narrative is meant to excuse the degree of repetition that sets in, but the casting doesn't really help Jones's cause. Not one supporting character is as vividly etched as Groundhog Day's Ned Ryerson, or even Alan Ruck's worrywort from Speed, still the pre-eminent high-velocity, high-concept transportation thriller of this kind. Gyllenhaal, granted, improves upon his Prince of Persia action man by a) putting a shirt on and b) tapping into a vein of goofy humour that gets us past the schlockier developments in Ben Ripley's script, but it's a pity his nemesis should be a lone milquetoast with not much motive and nothing to do with the real world. Vera Farmiga holds up her end as the Captain's commanding officer, but Jeffrey Wright is pretty ropey as the source code's originator and twitchy, limping red herring badass, and Monaghan seems, as so often, a second- or third-choice romantic lead; Liv Tyler's return to acting can't come soon enough, as far as this viewer is concerned.

After his largely interior debut, Jones busts out with helicopter shots of Chicago's intersecting streets and railroads, corresponding as they do to a line of inquiry in Ripley's writing about the forks in paths we arrive at in life. It's a committed bid for the Hollywood action big leagues presently topped by fellow Brit Christopher Nolan after Inception, and Jones does well by the widescreen stuff while retaining the sharp eye for detail Moon relied upon: as it was there, Chesney Hawkes' one-hit wonder "The One and Only" becomes a shorthand signifier of how truly hard it is to retain your individuality in the postmodern worlds these films describe. Source Code's middle ground, though, is just OK - indifferently directed filler, scarcely indistinguishable from a half-dozen other action movies - where Nolan, at his best, has managed some distance better than that. Confident, efficient Saturday-night entertainment, then, but - for all Ripley's believe-it-or-not references to parabolic calculus - not greatly more profound, mysterious or affecting than Tony Scott's Unstoppable.

Source Code is on nationwide release.