- "I don't trust him as far as I can shunt him! He's a mean old liar!"
- ―Duck talking about Diesel
Bumps is a magazine story. The first part of this stoy is called, Trouble in the Harbour Yard.
Diesel has arrived at the docks to help Duck and Percy with the workload. They do not like working with Diesel one bit, but Percy decides that perhaps they should give Diesel a second chance after all.
Percy and Duck have to share their shed with Diesel and, one morning, Diesel's driver releases his brakes too sharply and Diesel bumps right into Percy who is not at all happy. Percy is even more shocked that Diesel does not even apologise for his actions; no respectable engine should ever bump another engine. Duck agrees with Percy, but Diesel thinks it all very funny.
The trucks don't like Diesel either and whatever the oily engine tries to do, the trucks resist it. Sometimes, Diesel bumps the trucks so hard that they spill their loads. Percy and Duck knows the Fat Controller won't like it, but not wanting to be "tell-tales", Percy and Duck say nothing. This makes Diesel ruder than ever because he knows he can get away with it.
Then, one day, Diesel is shunting trucks full of china clay on the pier. Diesel's driver warns his engine to be careful, but Diesel does not listen. He gives the trucks a mighty bump and bangs them hard into the buffers, but the buffers are not secure. With a loud crack, the buffers give way and the trucks tumble into the sea.
Neither Percy or Duck tell the Fat Controller, but he soon hears all about it from the harbourmaster. The trucks are hoisted from the sea by cranes, but the china clay is lost. The Fat Controller is very cross and warns Diesel that he will spoil his chances again. Diesel says sorry and, this time, he really means it.
- This story, along with the first part, was adapted into the third season episode, Diesel Does it Again.
- The trucks are missing their faces in the final illustration.