Series 4: 4. Runaway Koko Children's animation in which the trains talk, think and do not need drivers. Koko's speed booster malfunctions and she speeds around Chuggington out of control. More ...

Koko decides to try for the High Speed badge - something no trainee has ever won. Emery wishes he still earned badges like the trainees do. For fun, he plays a 'pretend badge' game with Hoot and Toot, ...