Thomas & Friends S20E16 - Mike's Whistle

Based on the story of the same name from Small Railway Engines.

Duck's driver boils an egg in his whistle, which is now clogged and makes a funny noise. The engines tease Duck about his whistle, especially Mike who says engines without whistles are improper engines. Later, he pulls passengers on the line and encounters a cow. He blows his whistle so hard that it flies far away into a field. Mike insists they look for his lost whistle, but the passengers decide to whistle for him instead.