The elves are small dwarf-like humanoids with poined ears who live and work at the North Pole, creating all the toys for Santa Claus to deliver on Christmas Eve as well as helping him keep track of all the children to make sure they are nice.
The Polar Express
When the Polar Express arrives at the North Pole, the children look outside to find no elves. The Conductor explains that they are gathering at the center of the city to watch Santa give the first gift of Christmas to one of the children. Soon, the train arrives at the center of the city where the children find hundreds of elves gathering.
While trying to find their way back to the North Pole center after getting lost due to the runaway observation car, Hero Boy, Hero Girl and Billy end up in the communications room where they find a couple of elves doing some last minute work when an alarm sounds, signaling that a child has done something naughty. They find it to be a child from Maplewood, New Jersey who stuck some gum in his sister's hair. Being a last minute thing, they decided to give the child a break, but put him on the check-twice list for next year. After that, they take the pneumatic to get to the center of the city, claiming it is the only way to get there on time. The children decide to take the pneumatic too, but end up in a factory instead.
Later, the elves use a pair of zeppelins to carry the big bag of presents to the center. However, the Conductor notices that the bag is very close to the star on top of the big tree, so he calls out to the elves to increase their altitude and a few of the elves jump off, increasing the altitude of the zeppelins. However, the bag still hits the star, causing it to fall off, but some more of the elves, with ropes attached, jump off and grab it before any elves got hurt, the put it back on the tree.
The bag is soon landed on Santa's sleigh and four of the elves come to rescue the children while also saying that they knew they were there the whole time. Initially, Billy was hesitant to let go of his presents until one of the elves assures him the present will be in good hands.
When Santa shows up, the elves begin cheering, blocking Hero Boy's view while trying to see Santa. They cheer again when Hero Boy is chosen as the one to receive the first gift of Christmas, then carry him to the sleigh and cheer again when Santa declares the silver bell the first gift. They cheer one more time while also throwing their hats into the air after Santa leaves the North Pole to deliver the presents and celebrate. One of them sings "Rockin' on Top of the World".
Meanwhile, four of the elves get a handcar and use it to re-couple the observation car to the rest of the train, then fall down in exhaustion.