The Fat Controller is the Controller of the North Western Railway
Sir Topham Hatt is firm but funny and fair. He can be strict, but with a good reason and he deeply cares about the engines and also shows a fatherly side to them. He is quite a strong character and will remind the engines that he is in charge if they start to rebel against his authority. He does not stand bullying and even though he is usually serious, he does enjoy a good jolly laugh.
Despite his kindness and fairness, however, there are times where Sir Topham Hatt berates the engines for situations beyond their control, although it's usually because he still feels like their carelessness or ignorance played a hand in it. Like any son, he does hold a slight bit of respect for his mother, Dowager Hatt. But like all parental relationships, there are some things he finds more personal than others.
At times, Sir Topham Hatt can be the comic relief character, having high levels of irony and occasional slapstick. He can also be overhasty and forgetful at times and misplace priorities. He also has a slight sweet tooth, having a particular taste for crème buns, ice cream and milkshakes.
Sir Topham Hatt is a short, chubby gentleman. He usually wears morning dress, consisting of grey trousers, a white shirt, a black tie, a cream, yellow, blue, purple or grey waistcoat, a black tailcoat and a black top hat. He is most often depicted as having thinning grey, black or brown hair and brown eyes, while in the television series, he is depicted as completely bald.