is about what happens when an American couple - he's a good Christian and a model train geek, she's a reformed bad girl, an amateur photographer - take the train from Beijing to Moscow.

It's also about what happens when an Oscar-winning English actor by the name of Ben Kingsley decides to play a menacing Russian detective.

"To live life is not always a walk through the meadow," Kingsley's Grinko says in a thick accent, cautioning the rightly terrified tourist Jessie (Emily Mortimer) that things are likely to turn unpleasant.

He's right.

A morally complex if plot-wobbly thriller set on the Trans-Siberian Express as it rockets (well, creaks and groans) through snowy forests and forgotten towns, Transsiberian references The Lady Vanishes, Midnight Express, and a bunch of pics dealing with rail travel, drug smuggling, and nightmare tales of travel abroad. Alas, even Saw gets evoked in this Brad Anderson-directed suspenser: There's grisly business with Kate Mara and a hunting knife.

Jessie and Roy (an aw-shucks Woody Harrelson) have finished a teaching stint in China, and decide to take the long way home, on the legendary rail line that links east to west. Once an emblem of luxury, the train, in these post-Soviet times, has become alarmingly shoddy, but that's OK with locomotive buff Roy - even if they have to share their compartment with a pair of scruffy backpackers. Carlos (Eduardo Noriega) has tattoos and an eye for Jessie, and his girlfriend, Abby (Mara), has goth eyeliner and a disaffected air.

They also have a suspiciously heavy bag of Russian nesting dolls. How do you say heroin in Russian, anyway?

After a prologue featuring Kingsley at a creepy crime scene, Transsiberian takes off in a nicely talky fashion - as the gregarious Roy and the chain-smoking Jessie get to know Carlos and Abby, and vice versa. Though Harrelson's character never rises above the level of cartoon, Mortimer is terrific as the watchful, wary Jessie - with memories of a wild past brimming in her eyes.

"If I got rid of all my demons, I might lose my angels too," she says, when asked why she still smokes. But she's talking about other stuff, too. (And quoting Tennessee Williams in the process.)

Anderson has an interesting lineup of films to his credit: small, smart indies (The Darien Gap, Next Stop Wonderland), and dark, strange thrillers (Session 9, The Machinist - with a scary-thin Christian Bale). Transsiberian falls squarely in the latter category, and the director (he also cowrote) gives Mortimer's character, at least, serious dimension.

If the plot, with its unwelcoming and sinister Russians, lapses into B-movie cliche, Transsiberian also manages to pull off a couple of startling surprises - one of which seems to shock Mortimer's character as much as it shocks us.

She never quite gets over it.

Transsiberian *** (Out of four stars)

Directed by Brad Anderson. With Woody Harrelson, Ben Kingsley, Kate Mara, Emily Mortimer and Eduardo Noriega. First Look Studios.

Running time: 1 hour, 51 mins.

Parent's guide: R (violence, sex, profanity, adult themes)

Playing at: Ritz at the BourseEndText

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