Flag Waving! is a magazine story.
As Thomas leaves Wellsworth, the guard notices Annie's door is not shut properly and as soon as they pull out of the station her door swings open. The quick-thinking guard waves his red flag and stops the train. The Fat Controller praises him and a few days later, the engine crews hold a football match. Thomas wonders why the Wellsworth guard has his flag with him. The Fat Controller tells him that the guard is going to be a linesman and has to wave his flag when the ball goes off the pitch.