Series 3 of The Dark Railway Series was released in 2012. The series consisted of ten episodes.
- The Return of Sir Eustace Missenden - The railway's New Years Eve party has a few unexpected surprises.
- Like a Sir - Colin and Eddie try to pull a train in Eustace's place.
- 257 Squadron - Eustace spots a mysterious engine coming onto the line.
- Tender Moments of Tender Engines - Eustace becomes jealous of 257 Squadron.
- BR Blues - The diesels are being repainted, and Allan uses it to his advantage.
- Football Shortfalls - A football special is faced with numerous problems.
- Poor Leno - Colin and Eddie bring an old worn out engine to the railway.
- Super 8 - The diesel shunters are sent to take part in a film.
- Who Goes There? - The engines start disappearing just before Dave's return.
- Revenge of the Forgotten - Leanne has returned for revenge.
- Theo and Otto
- Sir Eustace Missenden
- 257 Squadron
- Sir Edgar Woolwinder
- Bob the Invisible Pink Sailor
- Mr. Dark
- Mr. Littlewood
- Maxen (mentioned)
Characters introduced Edit
- The Works Diesel
- The Class 24
- Mr. Davies
- Mr. Sims
- The Director
- Merecombe FC Team (do not speak)
- The Preservation Society (do not speak)
- Rodney (cameo)
- James (mentioned)
- Tangmere (mentioned)
- Sir Keith Park (mentioned)
- Anti Aircraft Command (mentioned)
Guest Actors Edit
- Nick Gagliardi as the Works Diesel
- James Littlewood as Bob the Invisible Pink Sailor and Mr. Littlewood
- Rhys Davies as Mr. Davies
- Anthony Sims as Mr. Sims
- Aaron Wilkinson as the Director
- This series is set between 1963 and 1965.