Stephen Hatt is possible third controller and the main antagonist of Season 3.
He is Charles Hatt's son and Sir Topham's grandson. He is currently in alliance with Ryan to cause mischef for Sodor and take control of the North Western Railway. He is later revealed to be the son of Simon Johnson. After framing Phil Aardman for building a doomsday device and taking over his railway, Stephen found that Charles Hatt was in fact not his biological father, and thus the railway was not his inheritance as he had thought. Phil stated that he would press the most severe charges possible, but ultimately did not press the severe charges as anticipated. Stephen was taken to court and recieved five years in prison.
- Season 3: Inheritance Parts 1, 2, 3, 4, 5, 6 and 7