Rusty to the Rescue is the fifteenth episode ever made in Season 4.
Rusty enjoys visiting the Bluebell Railway, but Rusty's driver is concerned that the line needs an engine, so Rusty consults with Douglas about finding one on the Other Railway. Douglas mentions that only Diesels travel to the Other Railway nowadays, which is where he found Oliver. That suits Rusty and the next day, he travels to the Other Railway, slipping past the Diesels by lying that he is an inspection Diesel. He finds a tank engine named Stepney in a siding and helps him to escape to Sodor.
- In the British narration, when Thomas' puffs past Rusty, he has Edward's whistle sound. In the American narration, he has his own whistle sound.