There are four known windmills on Sodor: one on Thomas' Branch Line, one on the main line, one near Killaban and Toby's Windmill on Toby's Branch Line. Each of the four windmills grinds wheat grown on Sodor into flour for use in making bread for the residents of nearby villages.
This windmill is located on the main line between Balladrine and Kellaby and its model has been seen in various locations since the fifth season. In the fifth and sixth seasons, it was shown on The Loop Line north of Crosby. Between the fifth and sixth seasons, its original sails, more similar to those of the Post Mill, were replaced by the set which it carries today. In the seventh season it was located on Edward's Branch Line between Wellsworth and Suddery. Since the eighth season it has been shown in its current position on the main line and footage of Thomas passing by the windmill with Annie and Clarabel is used for the intro of the New Series, as well the nineteenth season intro. The Tower Mill also once appeared in an unknown location in Stepney Gets Lost.
- The track layout changed in the seventh and eighth season.
- The bridge next to the windmill was removed in the eighth season.
- In the ninth season episode, Percy and the Oil Painting, Percy took the famous oil painter to the Tower Mill while looking for "The Spirit of Sodor," but the famous oil painter complained that it was too round.
- The model of the Tower Mill is currently on display at Drayton Manor.
- In the tenth season episode, Topped Off Thomas, Sir Topham Hatt's top hat was blown onto one of the sails of the Tower Mill.
- The ruined Tower Mill was originally going to appear in the aftermath of the storm in the 2005 special, Calling All Engines! but it was changed to the Sodor Suspension Bridge.
- The model of the Tower Mill is frequently used in promotional photos.