Series 7 of The Dark Railway Series began airing in 2017. The series had ten episodes.
- Futura - Mr Dark has a series of plans for the railway's future.
- Smashing! - The new arrivals settle in on the railway.
- Braking Bad - Caracus' first day doesn't go quite to plan.
- The Road to Colhapper - Allan has a decision to make.
- Ey Up? - The engines are baffled by the latest newcomer.
- The Red Herring - Barry is suspicious of a new freight train.
- Mothership Reconnection - The engines try to find out Five's secret.
- Rollerskate Disco - The new Junction railway museum is opened to the public.
- What a Clarence! - A mainline diesel multiple unit is rude to the engines.
- The Man in Overalls - Dave starts talking to Mr. Smash's apprentice.
- Theo and Otto
- Sir Eustace Missenden
- 257 Squadron
- Mr. Dark
- Mr. Smash
- Colin (as a ghost; does not speak)
- Owen (as a ghost; does not speak)
- Cammer (as a ghost; does not speak)
- Repulse (mentioned)
- Leanne (mentioned)
- Maxen (mentioned)
- Oliver Cromwell (mentioned)
- Mac (mentioned)
- Liz (mentioned)
- Brain (not named; mentioned)
- Caracus Smash
- Mr. Chairman
- Zeke Dark
- Cookham Manor (does not speak)
- 6697 (not named; does not speak)
- 1466 (not named; mentioned)
- Stuart Steel as Five
- Anthony Sims as Barry and the mysterious men
- Gwion Rhys Davies as Mr. Chairman
- David Seward as Caracus Smash's guard
- Freddie Veiga-Pires as Caracus Smash's driver
- Glenn Streeter as Caracus Smash's fireman
- Callum Hancock as Clarence
- This is the first season to include a regular voice cast rather than guest stars.