Stephen, nicknamed "The Rocket", is an early steam engine who works at Ulfstead Castle, where he takes visitors around the castle grounds and across the rest of Sodor.
- A Tale of a Small Green Engine (mentioned)
- A Turning Point for Edward (mentioned)
- How the Diesel Stole Christmas (cameo)
Stephen first appeared in the 2013 special King of the Railway. He would later appear through Seasons 17 through 21. He also appeared in The Great Race and made a cameo appearance in Journey Beyond Sodor.
He is currently voiced by Bob Golding in both the UK and US dubs.