One sunny day, Thomas is puffing along his branch line with Annie and Clarabelle. He arrives at Knapford Station, but is surprises to see a diesel engine zoom by at a fast speed.
Later at the Tidmouth Sheds, Sir Topham Hatt arrives and tells the engines that there is now a diesel on the island; who he is giving a trial to to see if he can stay on the island. The diesel's name is Class 40. Sir Topham Hatt has Thomas show the Class 40 around.
Thomas takes Class 40 to Knapford Station. The diesel turns out to be very rude. He tells Thomas that steam is out of date and that diesels will replace them.
Later at Knapford, Class 40 is waiting for his first job; it turns out to be a dirty freight train. He refuses to pull the train and says to get him coaches instead; because they are way more important. His driver argues with him. Suddenly, the Station Master comes outside and brings up how Class 40 was suppose to leave long ago and that his train is now blocking the line. Suddenly, Gordon crashes into the train; causing an accident. Later, Thomas arrives with the Breakdown Train to clean up the mess.
Later that night at Tidmouth Sheds, Sir Topham Hatt angrily tells Class 40 that he has failed the trial and to get off his railway. Thomas jokes to Class 40 about how he claimed to be so revolutionary. Class 40 growls in anger.
- Most of the episode was filmed in 2014.
- This is remake of an older video of Multi's older series.