One Bump Too Many is a magazine story.
Percy and Duck's job is to shunt trucks to be loaded and unloaded from ships at the big harbour. Working with trucks for so long, the two engines have grown accustomed to their troublesome ways. They always try to be calm with them and only ever bump the trucks as a last resort. Diesel, on the other hand, is less understanding. He believes that you need to show the trucks who is boss. Percy and Duck feel sorry for the trucks when Diesel's hauling them.
One day, as usual, Diesel was bumping his trucks about the yard. Suddenly, he felt a bizarre crunching. Diesel's guard and Percy's driver went to investigate. The men could not believe their eyes - with all the bumping, Diesel had broken his own buffers. Diesel was at the works for a whole week, but it was a lot longer than that before Percy and Duck let him forget his careless accident.
- The events of Diesel Does it Again are mentioned.
- In the ninth illustration, Diesel's steps are not coloured in.