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.
- Airhead: Harold starts to get a little boastful and cocky.
- Painful Memories: Henry has a traumatizing near miss with explosive fuel wagons and he now fears for his safety.
- An Unfortunate Coincidence for Jock: A tree causes trouble for Jock during a storm.
- Episode 32
It is likely there will be more than ten episodes. One of them will be Christmas themed. Edward will have the main role in the last two episodes.
- Donald and Douglas
- Sir Topham Hatt
- Arry and Bert
- Diesel 10
- Sir Handel
- Peter Sam
- Ivo Hugh
The following are confirmed
The following are likely to appear
- By the end of the season, all original 11 NWR engines will have had at least one main role in The Engines of Sodor.