Thomas & Friends (1984)

S06E11 The World's Strongest Engine

With Henry sidelined due to an accident, Diesel returns and irritates the other engines by claiming to be the strongest. Eager to demonstrate his strength, he attempts to haul 20 trucks simultaneously. However, the trucks' brakes are engaged, leading to a broken coupling that sends Diesel hurtling down the yard. His overconfidence backfires, showcasing that strength isn't everything.