Thomas was once supposed to take Sir Topham and Lady Hatt to Sir Topham's birthday party, but instead of them, he found Sir Lowham at Maithwaite. Unaware of who he actually was, Thomas mistook him for the Fat Controller, though he did notice he was acting odd, such as calling Thomas his "good friend". Sir Lowham asked Thomas to take him to the Whispering Woods, where they met Edward and some children, who Sir Lowham played hide and seek with. Thomas confided in Edward his concerns about "the Fat Controller's" weird behaviour, though was afraid to ask him himself, believing he would look silly. Thomas convinced Sir Lowham that they needed to head to the party, though he told Edward to let the children continue to play.
Thomas eventually stopped at a red signal, where Sir Lowham disembarked the train and walked to the signal box, much to the surprise of the signalman, who also mistook him for Sir Topham. Sir Lowham played with one of the levers, sending Gordon and the Express, filled with important passengers for his brother's party, onto a branch line. Thomas was very surprised at "the Fat Controller's" odd behaviour, but again said nothing about it. They returned to Maithwaite, where the Stationmaster revealed Sir Topham and Lady Hatt went on Bertie to the party. Thomas finally asked "the Fat Controller" about his behaviour, who admitted he was in fact his brother.
The two then set off to find Bertie, who had broken down on the side of the road. The real Fat Controller berated his brother for the confusion and delay he caused with his "old tricks", before insisting they hurry to the party. Afterwards, Thomas corrected the problems Sir Lowham had caused and everybody was able to enjoy the party.
Sir Lowham Hatt is jolly, mischievous and enjoys playing hide and seek with the children. He has a reputation for playing tricks and enjoys having fun, with no concern for the confusion and delay he may cause. He seems to know little or nothing about railways; he once went into a signal box and pulled the lever, switching Gordon to a branch line. He can be said to be the complete opposite of his brother. He dresses exactly like Sir Topham but has a moustache. It is unknown how or why he got his knighthood.
Just like his brother, Sir Lowham wears morning dress, consisting of a black tailcoat with grey trousers, a white shirt, a yellow waistcoat, a black tie and a black top hat.
- Keith Wickham (UK)
- Kerry Shale (US)
- Blas García (Latin America)
- Rokurō Naya (Japan)
- Øyvind Borgemoen Lyse (Norway)
- Eberhard Haar (Germany)
- Jan Gullivan (Germany; Audio Books only)
- Mikołaj Klimek (Poland)
- Bernard Demory (France and French speaking Canada)
- Aku Laitinen (Finland)