Sir Topham Hatt, nicknamed "the Fat Controller", is the manager of the North Western Railway.
The Fat Controller is firm but fair. He can be strict, but also shows a fatherly side to the engines. He is quite a strong character and will remind the engines that he is in charge when they start to rebel against his authority. He does not stand bullying and, even though he is usually serious, he does enjoy a good laugh. Despite his kindness and fairness, however, there are times where he berates the engines for things beyond their control.
The Fat Controller is a short, stout gentleman. He is usually dressed in a black suit with grey trousers, a cream or yellow waistcoat, a black tie, and a top hat. He is most often depicted as having thinning grey hair and blue eyes.