|This article is about 'the annual story'. You may be looking for 'the steam engines, the book or the Story Library book'.|
Bill and Ben is a 1999 annual story.
Bill and Ben's nameplates have been removed to be cleaned, so the twins pretend they are each other. BoCo gets confused, but gets revenge by pretending to be his twin CoBo.
- This story is a call back to the episode "The Diseasel".
- In most of the illustrations, the tops of Bill and Ben's boilers are black. Also in some of the illustrations, their sandboxes are grey.