"I'm saying timber!"
Diesel Headquarters II was built sometime after the events of The Quest Begins and before The Diesel Army (episode). It has a crane and smelting devices for scrapping and melting down steam engines. There is another section that is almost identical, but this one has an entrance to the sea with a storage area for ships. Connor, Ivo Hugh, 089 and Lady were once held captive here, but they were saved by Gold Leader and Scruff. The fortress was then destroyed by the latter.
- This is the only Diesel Fortress that was destroyed on-screen.