Rosie & The Signal is a Potential Plotline episode.
Rosie teases Spencer with a train of coal trucks and tricks Dennis into staying in the shed all day. The two are furious, and when Rosie gets conceited about being asked to take a special to the junction they seize thier chance and warn her about fictional "backing signals". Rosie believes them, and Spencer catches her backing from a signal outside the junction, allowing them to get renvage on the small pink tank engine.
- The Fat Controller (does not speak)
- Billy (cameo)
- Arthur (cameo)
- Neville (cameo)
- Molly (cameo)
- First apperences of Billy, Arthur, Nevile, Spencer and Dennis' CGI faces.
- Spencer isn't able to go on the branch line, so he shoudn't have been outside the Ffarquhar Sheds.
- In a close-up of Rosie's wheels when she reverses from the signal, a wire is visible.
- When Rosie says, "Stay in the shed today, Dennis. The Fat Controller will come and see you", her eyebows are missing.