Scruff "the Scruncher" is a boxy tank engine, who works at the Waste Dump alongside Whiff.
Scruff was brought to Sodor to work at Whiff's Waste Dump. He hates being cleaned and, when Thomas once tried to have him cleaned, he ran away and hid in a siding until he was coaxed out with the promise of being allowed to shunt rubbish trucks. He once had to go to the Sodor Steamworks to have his "scruncher" mended and later that day, he helped Gordon tidy up the waste dump before the inspector arrived.
Scruff once had to be repainted and he enjoyed his new look so much that he did not want to get dirty. He then went round the Island, looking for a new job, until Gordon reminded him that he was most useful at the rubbish dump with Whiff.
In the eighteenth season, Scruff broke down at Crocks Scrap Yard. So Samson shunted him to the Steamworks. After he was fixed, he overheard the Fat Controller saying Samson had taken his car to the scrapyards and Scruff told the Fat Controller he knew a shortcut. He then made it to the scrapyards just before Reg could grab it.
He and Whiff later helped out with Thomas when he ordered himself to be covered in waste, so the tank engine could play a trick on Diesel. They later attended Sir Robert Norramby's Christmas party.
Scruff, alongside the other engines wanted to participate in the Great Railway Show, though the Fat Controller didn't pick him.
Scruff is a grubby little chap, with a lime green boxy shape. He likes to sometimes get dirty during his job. He is more than content with "scrunching" and shunting rubbish trucks at Whiff's waste dump and has few other aspirations. He has been known to run in fear and hide away from things that he does not quite understand and can find having all the focus on him a little daunting. It seems, at times, that Scruff would rather be busily working in the background. However, he is cheerful to welcome engines to the waste dump and happy to have others join in with the "scrunching". He is notably, perhaps, one of the few engines on Sodor with little desire to be clean and presentable. Scruff's main motivator is being able to just get stuck in and knuckle down with his jobs.
Scruff is based on No. 9369 "Musketeer", a Sentinel 100 HP BE Type chain-driven vertical-boiler steam locomotive built in 1946 by Sentinel Waggon Works. "Musketeer" is preserved by the Northamptonshire Ironstone Railway Trust.
Scruff is painted lime green with dark green stripes, funnel and front. He has brass nameplates on either side of his tanks, although his name is only written on these in merchandise. In the television series, the plates are blank.