Geoffrey, shortened to Geoff, is a friendly diesel who works at the locomotive works (later called the Steamworks) at Crovan's Gate.
During the episode Testing Times, Geoff was seen taking Barry outside to a water tower to do his boiler test in using water to reach two hundred psi. The former Fat Controller, Sir Charles Topham Hatt said to not above ten psi is the water gauge rising at that instinct. Barry would be happy for himself to have this up at two hundred and ten psi in a couple of days before Sir Charles Topham Hatt could make a boiler certificate to Barry. Geoff left Barry and had to deal with other things for the works station.
In 2009, when Gordon had his accident with the lorry, Geoff told Bear that he had no orders to move Gordon into the steamworks, which made Bear worried. It was later revealed that Norman Spencer had plans to send Gordon to the National Railway Museum instead of having the big blue engine repaired.
Later on, Geoff helped Thomas to the steamworks after the blue tank engine's accident with a car at a crossing. He also told Thomas that Emily Helen Hatt had a surprise for him, which turned out to be Lily. He also had George being brought into the works to be repaired following another accident, this time involving Mavis after Thomas told her about the steamroller's first alleged accident with Colin in 1931.
Geoff is a British Rail Class 47.
- Barry the Rescue Engine - Testing Times
- Season 5 - One of a Kind (cameo)
- Season 1 STMY - Ode to George Carlin, The Missing Engine, Doncaster Drawn (mentioned), Separation Anxiety (mentioned), Aftermath, Homecoming and Genesis of a Grudge
- Season 2 STMY - Swan Song (does not speak), Caden (does not speak) and Endgame (cameo)
- Geoff is WildNorWester's name for the unnamed Works Diesel that appeared in the RWS book "James and the Diesel Engines".
- In Sodor: The Modern Years, he became the equivalent to the TVS character Victor.
- Geoff's face may be based on BoCo's.
- In the episode; Homecoming, Lily refers to Geoff as 'Geoffrey.' This is his full name, as 'Geoff' is just an abbreviation.