Know-It-All

"Hey! Hey, you! Yeah, you! Do you know what kind of train this is?"

- Know-It-All when first meeting Hero Boy.

Know-It-All is one of the children that rode on the Polar Express. He is talkative and he seems smart at first, but it is soon apparent that he only wants to be smart and needs the ability to learn more. He is mocaped and voiced by Eddie Deezen who also voices Mandark from Dexter's Laboratory.

Journey to the North Pole
Hero Boy first meets Know-It-All on the train right after he takes a seat. Know-It-All asks Hero Boy if he knows what kind of train they are on, leaving him confused. Hero Girl joins in the conversation and answers the question by saying it is a magic train that goes to the North Pole. Know-It-All proceeds to give a detailed explanation of the train before noticing Herpolsheimer's outside and calls out to the other children to come and see it. The store features a Christmas display with a pile of presents, to which Know-It-All exclaims, "I want all of them!"

When the Conductor punches the children's tickets, he puts "LE" on the one from Know-It-All, who claims the Conductor is a show off with the way he punches tickets and questions what the letters mean. Hero Girl would later get the same letters. He is surprised when they stop at Billy's house, as he thought Hero Boy was the last passenger. Billy turns the trip down, but changes his mind and runs after the train as it leaves. However, since he has trouble getting on, Know-It-All suggests Hero Boy to pull the emergency brake, which he does, stopping the train and allowing Billy to get on board. When an angry Conductor storms in, Know-It-All tells on Hero Boy, despite it having been his suggestion.

When Hero Girl goes to give Billy hot chocolate, Know-It-All and Hero Boy try to persuade her out of it with the former saying it is against railroad safety regulations for children to cross moving cars without a grown-up. The Conductor eventually shows up to assist her. He then warns Hero Boy when he leaves to give Hero Girl her ticket back. Soon, the Conductor comes to punch Hero Girl's ticket, but when she cannot find it, he takes her to the back of the train. Know-It-All says she might get thrown off the train and points out that they might slow down for her, but not come to a complete stop, giving Hero Boy the idea to stop the train again until he finds the ticket sticking onto the air vent above the brake, grabs it, and goes after Hero Girl and the Conductor.

After the train passes through Glacier Gulch and the Ice Lake, Hero Boy, Hero Girl, and the Conductor return to the passenger cars. Know-It-All tries explaining the events to Hero Boy, unaware that he actually experienced more of it. However, he did not believe the train was really on the ice, thinking moonlight and the atmosphere just created an optical illusion. An uninterested Hero Boy heads to the observation car.

At the North Pole
The train arrives at the North Pole and the Conductor tells the children about the first gift of Christmas, to which Know-It-All asks who will receive it. At the North Pole Square, the Conductor mentions the time being five minutes to midnight and Know-It-All points out how it has been that time for the past four minutes. He watches Hero Boy and Hero Girl going back to get Billy and follows them through the city, though he is never seen.

In the big bag of gifts, the other children find Know-It-All in the bag with them after he pulls on Billy's leg, likely thinking it was a present. He says he is in the bag to make sure he is getting everything on his list, but only found one present with "a bunch of stupid underwear." Soon, they arrive back at the Square and Hero Girl points out the time still being 11:55 and Know-It-All claims they will not be late since the time has been the same for the past hour. The bag is landed on Santa's sleigh and the elves go to rescue the children from it. Know-It-All tries to appear innocent by saying he was only following the others. He is also the first one to slide down the bag.

When Santa Claus arrives at the Square and speaks to the children, Know-It-All impatiently asks Santa to pick him as the one to receive the first gift with Hero Girl trying to make him behave, but he does not stop until Santa tells him to be patient and show a bit of humility. Know-It-All also watches Hero Boy receiving the first gift and Santa Claus flying away in his sleigh.

Return Trip
Before boarding the train for the ride home, his ticket is punched again. He looks at it and reads "LEAN", though is unaware that his fingers is covering a letter and that it really says "LEARN". The Conductor explains his mistake, which makes him snap back, but when he takes a second look and sees the R, he apologizes and gets on the train with the Conductor smiling. Like the other children, he asks to see Hero Boy's silver bell and feels sorry for him after finding out he lost it.

Know-It-All sits next to Billy during the trip. Before Billy gets off the train, Know-It-All asks where he is going and Billy explains that the train has stopped at his house. He also says goodbye to Hero Boy before he gets off the train, still feeling sorry about the bell. He points out, however, that, "It's the thought that counts."

The Polar Express: The Video Game
Know-It-All is one of the children whom Hero Boy helps finding their ticket, which was stolen by Scrooge. Before everyone goes to find them, he brags about how he never loses his ticket before realizing it is gone. His ticket was in the dining car and Hero Boy had to have a food fight with Scrooge's friends to get it back. When Know-It-All sees the mess, he tells Hero Boy that throwing objects inside train cars is against railroad regulations, but thanks him for finding his ticket and advises him to leave the dining car before the cook sees the mess. Know-It-All is also one of the children who does the big thanks for helping find their tickets, then advises everyone to take their seats since regulations forbids blocking fire exits, which annoys Hero Girl. Next, he appears as one of the children cheering Hero Boy during the final battle with Scrooge.

Later, he appears on board the zeppelin with Hero Boy, Hero Girl and Billy. Like in the film, he tries to act innocent by telling the captain he was only following the others. When the captain asks for their help, Know-It-All asks if him helping will make him the first to see Santa, which annoys the other children. After Hero Boy returns from driving the zeppelin, Know-It-All complains about how bumpy the ride was.

Trivia

 * While Know-It-All does not appear in The Polar Express book, one of his lines, "Who gets the first gift of Christmas?" is equivalent to a line in the book, "Who receives the first gift?", which is said by all of the children.
 * Know-It-All says that the train is a Baldwin 2-8-4 S3-class Berkshire type steam locomotive built at the Baldwin Locomotive Works in 1931 and weighs 456,100 pounds. The Baldwin Locomotive Works built 35 locomotives of the S3-class for the Erie Railroad, but they were built in 1928 and weighed 457,500 pounds.
 * In comparison to Pere Marquette 1225, the train's basis for both the book and the film, it has the same wheel arrangement, but it weighs 442,500 and is a member of the N1 class, which were built at the Lima Locomotive Works in 1941.

Quotes

 * "Yeah, I know it's a magic train. Actually, it's a Baldwin 2-8-4 S3-class Berkshire type steam locomotive built in 1931 at the Baldwin Locomotive Works. It weighs 456,100 pounds and..."
 * "Hey, look, everybody! Herpolsheimer's! Herpolsheimer's!"
 * Wow! Look at all those presents. I want all of them.
 * "Boy, that guy sure likes to show off with his ticket punch. Look what that wise guy punched on my ticket. 'L-E.' What the heck does that mean?"
 * "Ah, it's just another pick-up. That's weird. I thought you were supposed to be the last one."
 * "He did!"
 * "You know, Montezuma, the king of the Aztecs would drink 50 quarts of hot chocolate every day. It was thick as mud and red. He put chili pepper in instead of sugar. Get it? Hot chocolate?"
 * "Hey, you missed it. We rode down some really sharp hills. And then, we were on what looked like a frozen lake. But I know it was just an optical illusion caused by moonlight atmosphere. He said the train was actually on the ice, but I said it was impossible because you can't put a train track... Hey, where you going now?"
 * "Who gets the first gift of Christmas?"
 * "Hey, what gives? It was five minutes to midnight four minutes ago!"
 * "Same as you, I'm checking out my Christmas presents. I want to make sure I've got everything on my list. All I got was one present and all I had was a bunch of stupid underwear!"
 * "I was just following them."
 * "Hey! Ow!"
 * "Pick me! Pick me! I want the first gift! I want the first gift!"
 * "'LEAN'? Whatever that's supposed to mean?"
 * "Hey, are you saying I don't know how to...?! Oh. I'm sorry. It says 'LEARN'. My mistake."