Once my parents assured me that I’d still be receiving presents, I got over the whole Santa thing pretty quickly. So it was with a cynic’s attitude that I saw “The Polar Express,” the new computer-animated Christmas phantasmagoria directed by Robert Zemeckis. And while it’s certainly not a Yuletide film for the ages, it’s winning enough to satisfy children and parents for at least this season.

Chances are, you know “The Polar Express” as a children’s book that’s been read to you, or that you’ve read to a wide-eyed child. At its best, “The Polar Express” captures the sleepy wonder of the book; at its worst, it’s as loud and gaudy as a shopping mall at the North Pole.

The movie opens on a little boy trying to sleep on Christmas Eve, torn between anticipating the big guy’s arrival and stifling the creeping suspicion that he doesn’t exist. In these scenes the stylish animation sets a dreamy tone that makes its surrealistic flights of fancy almost believable. The first fantastical tangent is the hardest sell, but it is in fact a lovely moment when the boy incredulously trudges out into the winter night and, all of a sudden, sees his street host to a giant, ethereal train.

From outside of the train pops the conductor (Tom Hanks), who insists the boy board the Polar Express, a train with one destination: Santa’s North Pole. Part Peter Pan, part Pied Piper, Mr. Hanks’s conductor collects children who are in dire need of Christmas lessons. On the train, the boy meets others like him, including a spoiled know-it-all, a plucky, self-assured girl (ripped from the pages of Disney feminism), and a dour sad-sack who looks like he belongs on the side of a milk carton.

From there, the breakneck pace accelerates like – well, a locomotive. Three roller-coaster set-pieces (literally) will leave the hearts of the little ones in their throats, and there’s a beguiling scene featuring a small army of dancing, flipping, and step-dancing waiters delivering cups of hot cocoa with laser-guided precision. One breathtaking scene follows a prized Polar Express ticket as it flies out of a window, into the mouth of an eagle, and surfs various wind currents back into the clutches of our hero.

My favorite moments in the film involve the explanation of how, in fact, Santa and his elves (who speak in hilarious, squeaky Yiddish) get all the world’s children their presents in one night. These should quiet even the most inquisitive young sleuth.

In the tradition of great kiddie films like “Willy Wonka and the Chocolate Factory,” “The Polar Express” is also occasionally creepy. Scenes featuring a Christmas toy graveyard, and a menacing hobo character (also played by Mr. Hanks), are scary and completely appropriate.

It should be noted that the film breaks new ground in animation (don’t they all?), further perfecting the process of motion-capture animation that helped bring the character “Golem” alive in the “Lord of the Rings” movies. This time the actor shining through – in just about every pixel – is Mr. Hanks. His vocal and physical performances as the conductor, the hobo, Santa Claus, and three other characters are virtuoso. While the photorealistic animation sometimes renders its humans as mannequins, the fluidity of the actual actors’ movements imbues the images with an eerie humanity.