Season 4 began airing on April 22, 2017 and, if everything goes to schedule this time, finish in December.
- The Great Railway Heist: A truck full of gold is stolen, and everyone is determined to find the burglars.
- Jim's Tale Jim tells the engines his story.
- Steaming Sausage: Rheneas gets back at Sir Handel and Peter Sam for teasing him about his leaking steam problem.
- Diesels and Dragons: Diesel 10 is up to his old bullying antics, but Percy might have a way to get him to make a fool out of himself.
- Donald and Douglas
- Sir Topham Hatt
- Arry and Bert
- Diesel 10
- Sir Handel
- Peter Sam
- Ivo Hugh
The following have been confirmed
The following are likely to appear
- Bill and Ben
- Mr. Percival
- Blister I and II
- Sigrid of Arlesdale
- By the end of the season, all original 11 NWR engines will have had at least one main role in The Engines of Sodor.