Build or Bust! is a magazine story.
The roof of Wellsworth's town hall is in need of repair. Percy is sent to collect the slates and timber, but a signal failure makes him late. Then, Lorry 1 and 2 roar past. Percy explains the situation and the horrid lorries race off to collect the supplies for Percy; just to prove that roads are better than rails. The horrid lorries are racing too fast and when they arrive back at Wellsworth, Lorry 1 smashes into a wall. Lorry 2 can't stop either and bashes straight into the back of Lorry 1 - sending timber and broken slates everywhere! The builders are not happy; they have to repair the town hall's roof and rebuild the wall!
- Percy, Lorry 1 and Lorry 2's drivers are missing.