Happy Hook is a stationary non-sentient crane based at the Vicarstown Dieselworks.
Happy Hook was old and had not been repaired for a long time; as a result, Dart complained about the crane frequently. Kevin was then brought to the Dieselworks to do the jobs that Happy Hook could not, and enjoyed playing with it. When the Dieselworks was rebuilt, Happy Hook was restored.
When Diesel wanted to compete in The Great Railway Show, Happy Hook assisted in his plan to be chosen by putting crates on top of Den, Dart and Paxton. It later dropped a crate on Diesel after Dart was bashed into it.
Happy Hook later carried Daisy when Diesel bumped into her so that the engineers and workmen could find out what was wrong with her.
Happy Hook's cab is painted orange, while its tower and crane arm are painted grey.
- Happy Hook is the third non-sentient crane in the series to be named on screen (the first being Ol' Wheezy and the second being Hee-Haw).