|The Thin Controller|
|Position||Head of the Skarloey Railway|
|Arrived on Sodor||Unknown|
In the episode Diesels and Dukes, The Thin Controller was absent in this episode and a substituting controller took over for him while he was away. The substituting controller turned out to be Mr. Fergus Duncan, who is the controller of the newly formed Arlesdale Railway following its wonderful grand opening and making an extension to Peel Godred which the old Mid Sodor Railway once ran on. It was during the extension, Duke was found by two clergymen after one of them fell through the roof of his railway shed. The controller also wasn't seen in two episodes of Season 1.
The Thin Controller is mentioned by the narrator in the twenty-sixth episode, Gordon's Promise. He was with both The Fat Controller and The Small Controller who launched a tourism campaign which brought people from England to see the Island of Sodor from their point of view. The engines were so exhausted at this, especially the main line engines such as both James and Henry.
The Thin Controller told the engines that a new engine will be built in the workshops at Crovan's Gate. He told them this after the engines had reprimanded both Sir Handel and Duncan about comments made against Rusty.
The Thin Controller is mentioned once again, this time having a meeting that was made by acting director Norman Spencer. The stationmaster gave Emily Helen Hatt his whereabouts and she texted him about the signal crisis, but he had his phone switched off and Sir Stephen Topham Hatt did not see the funny side of it from his point of view. In the Season 1 STMY episode, Ode to George Carlin, he was told by Duncan that his twin brother on a railway in Wales had been repainted and that he wanted to be the same in tribute to George Carlin. The man said that the workmen can do that if Duncan wants it done by now. Then he spoke about Duncan's livery to Peter Sam and the other engines at the sheds.
Mr. Peter Sam said that Duncan will wear this livery for a short time on the railway until further notice. He then frowned and said to the other engines, including Duncan that the new livery will be worn by him for a little while rather than a short time on the railway in tribute to George Carlin.
- Season 3 - Gordon's Promise (mentioned)
- Season 5 - One of a Kind
- Season 1 STMY - Ode to George Carlin
- Season 2 STMY - Arrogance, Storm Damage (stock footage, cameo), Confidence
- Winds of Change (mentioned)