‎The Troublemakers‎ (1953)

Original title: Die Störenfriede

Schorsch and Franz are two rascals who are full of mischief and constantly tease both their teachers and their fellow pupils. Vera, the new classmate, decides to put her foot down and bring an end to the poor situation. With skill, patience and the help of the other pioneers she finds out about the troublemaker’s love for miniature trains and tries to direct their redundant energy onto the right track. However, Vera and her pioneers have to overcome some resistance before Schorsch and Franz finally change their behavior and become better classmates.