|The Old Mill|
|Age||Built in 1897|
|Status||Preserved - now a museum.|
After both Frank and Olivia arrived at Marthwaite, The Old Mill said that the tank engine had been doing some quick learning and she actually thanked him for it. She got confused and rather scared about this because the passengers didn't say a word about her. Thinking this was too much for her, Olivia hadn't got the idea of a building actually talking to her and a new railway that became so much strange. Both The Old Mill and Frank got into the situation saying that the mill once handled both flour and grains. He apologized for scaring her and she accepted it saying that her adjustments had to be done quickly under her own command. One of the blister twins passed with a works train in the opposite direction and the two engines left the area. Frank later told her that the old mill had been turned into a museum following its closure in 1964.
After a storm in 2011, it was revealed that Atlas, an engine who worked on the Mid Sodor Railway, was the Old Mill. The mill building endured heavy damage from the storm. Atlas ended up being purchased by The Thin Controller for the Skarloey Railway in exchange for helping the Old Mill Museum rebuild and recover.