|Age||47-68 (As of 2011)|
Sheffield used to work at a steelworks, known as Sixteen. He wanted to go pass a danger board in which he did which was sent to the back of the shed and having some of his parts taken down. He was bought by a heritage railway in 1971, restored to full working condition, and given the name 'Sheffield'. He also learned about his first Christmas on his heritage railway, and was done up as Percy on Day Out With Thomas Events, 'once or twice'.
Stephen Topham Hatt wanted to buy one of Wilbert's brothers so Sheffield ended up being bought and on his first day, he had the same accident like James did with some coaches, but with empty ballast cars for Sheffield. He and Duck didn't see eye to eye until he revealed to Duck and Donald that he was Sixteen, and that he was trying to break his habit of being rough with trucks.
Sometime later, Sheffield had to take over on the Kirk Ronan branch for Eric as the large tank engine went for his five yearly service. The trucks caused trouble along the line with a runaway which they crashed into the harbor shed and banged into a rusty Brian. After Brian was restored, he was permanently assigned to Sheffield.
Sheffield listened carefully to Duck's instructions to having to work half of the Arlesburgh branch line after Hugh rammed into the bridge. He stated that Thomas and James' theories were useful in solving the mystery of who broke the bridge in the first place.
In Winds of Change, Sheffield and Henry were talking to Shane at the engine sheds at Barrow-in-Furness. After Henry left, Sheffield told Shane the reasons diesels replaced steam engines. He was at the level crossing speaking to George with both Toby first and later, Mavis after the Troublesome Trucks made her collide with the rude steamroller. In Taking Care of Christmas, he talked to Iris about Christmas and how she should be celebrating it rather than not taking part in it for the sake of the NWR.
In Caden (the episode), Sheffield was assigned to work in the titular character's yard after failing due to contaminated fuel (he had also done this when Caden was in for service in 1996). The two augured for a bit until Miss Hatt reassigned him back to the Wellsworth Branch, which is where he had been working for the latter half of Season 2.
Sheffield is a Hunslet Austerity saddle tank engine, much like Wilbert.
- Season 5 - Doubts (does not speak), Ruffled Feathers, Sheffield's Secret, Flying Fish, Darkest Hour and Desperate Times
- Season 1 STMY - A Change of Scene (cameo), The Missing Engine, Fame and Misfortune (cameo), Separation Anxiety (mentioned), Last Laugh (does not speak), Aftermath, Homecoming (does not speak), Genesis of a Grudge (stock footage, does not speak) and Taking Care of Christmas
- Season 2 STMY - Swan Song (cameo), Engines of All Trades (does not speak), The Thin Clergyman, Unwanted (does not speak), Dime For Trouble (cameo), Caden and The Devious Way (cameo)
- For Season 1 STMY, Sheffield was slightly modified to make his wheels and livery reflective.
- When Sheffield was made a new model for Season 2 STMY by WildNorWester, his livery slightly changed.
- Part of Sheffield's faces appear to be based on Gordon's.
- Sheffield is the same class as Wilbert, a Hunslet WD 0-6-0ST.