Denzel Washington and Tony Scott would have been good together in preschool - two playmates off in the corner, monopolizing the toy cars and trains, slamming them into one another and making lots of big, kabooming explosion noises.

A star and a director who clearly enjoy each other's company, Washington and Scott have made five action-packed pictures now, including one in a submarine (Crimson Tide), one on a subway (The Taking of Pelham 123), and now, with Unstoppable, on a train rocketing down the tracks - no brakes! hazardous chemicals! Rosario Dawson on the horn from HQ!

"Inspired by true events," we're informed at the outset, Unstoppable rumbles through central Pennsylvania, where, in some seemingly ordinary rail yard on some seemingly ordinary day, a nincompoop freight engineer steps out of his cab with the engine on and the brakes off. Before you can yelp "Yo, moron!" the train has started rolling away. And it's picking up speed.

Toss in 150 school kids on a field trip to learn about rail safety (ha!), a deadly curve of elevated track in the bustling burg of Stanton, a CEO looking to cut budgets, and a bunch of state troopers in fierce (and futile) pursuit, and you have the makings of a real crisis.

To wit, Ms. Dawson, in a role requiring much knitting of brow and pulling back of hair: "We're not just talking about a train here. We're talking about a missile the size of the Chrysler building, bound for highly populated areas!"

Luckily, there's veteran train man Frank Barnes (Washington), who thinks he might be able to chase down the runaway skyscraper, I mean locomotive, link up to it from the rear, apply the brakes, and slow the thing down. His reluctant partner in this heroic enterprise is Will Colson (Chris Pine), a rookie conductor with a messy personal life.

It takes awhile for the old man and the novice to come to terms - generational friction, dueling work ethics, general grousing. But by the end, the two are a virtual daredevil team, hopping cars and couplings at 60 m.p.h., risking life and limb to stop the train while it's still on the rails.

Scott shoots and edits Unstoppable with roller-coaster momentum and an eye (and ear) on that roaring tonnage of steel. There are fast, jerky cuts, thundering sound effects, angles that play up the train's size and speed. An old hand at TV commercials, Scott digs into his kit bag and comes up with enough visual and aural tricks to keep audiences' attention as Mark Bomback's thoroughly unsurprising script plays itself out.

Although Unstoppable was made well before Deepwater Horizon went kablooey in the gulf, it's hard not to see parallels between the out-of-control oil rig and the out-of-control train: lax oversight, cost-cutting, numskulls with their hands on the switch (or not on the switch).

So where were Denzel Washington and Tony Scott when we really needed them?EndText

Contact movie critic Steven Rea at 215-854-5629 or srea@phillynews.com. Read his blog, "On Movies Online," at http://www.philly.com/philly/blogs/ onmovies/