Broken Biscuits is a De Agostini magazine story.
Diesel tells Percy that he is to take biscuits from the factory to the school for a party tomorrow. Percy warns Diesel not to go too fast otherwise the biscuits will break. Diesel boasts that he does not puff along the line like a steam engine and that the biscuits are safe with him. Unfortunately for Diesel, the trucks overhear.
At the factory, the trucks are loaded with biscuits and Diesel starts to pull them to the school. The trucks tease Diesel about his speed, which angers Diesel who goes faster. Diesel goes so fast that he derails and ends up in a pond. The boxes of biscuits burst open and a family of ducks swim up and eat the crumbs. Luckily, Percy is puffing past on the other line. He offers to collect some more biscuits and says that Diesel can stay and have a party with the ducks.