Thomas and Daisy is a Potential Plotlines episode.
Plot: One day Thomas warns Daisy that the high ravine viaduct is not safe. But Daisy doesn't listen, and she oils away. Later, Percy tries to stop Daisy. Daisy runs out of oil. The high ravine viaduct starts to collapse. Thomas rescues Daisy. Sir Topham Hatt scolds Daisy for a year for ignoring Thomas' advice.