The Trolls and the Christmas Express (1981)

The Trolls and the Christmas Express is an animated classic about six roguish trolls who are determined to sabotage Christmas by infiltrating Santa's village disguised as elves. After a week of wreaking havoc but still not completely ruining Christmas, they are about to give up when they get a devilishly clever idea. On the day before Christmas Eve they get the reindeer dancing and singing songs all night long. The poor reindeer are so tired the next day that they cannot find the energy to pull Santa's sleigh. Christmas looks like it has finally been ruined - but everyone knows you can't stop Christmas! The elves quickly devise a plan to link the train from Santa's village with tracks that travel all over the world. Santa can deliver the toys using the Christmas Express.