Chuggington (2008)

S3E12 Skylar's Squad

Skylar is conducting rescue training with the trainees, and those who succeed will earn high visibility stripes and a spot in Skylar's Squad! To support Skylar, Olwin takes Hoot and Toot for some additional practice. They engage in a game of hidey chuggers, where Hoot and Toot attempt to locate Olwin. They believe they've caught her voice echoing through a tunnel in the mountain, but they’re actually just chasing their own echoes.