Arthur took great pride in his spotless record, which he soon lost after colliding with Duck's trucks in an incident largely provoked by Thomas. However, this spotless record was soon amended, after Thomas apologized to him for causing the accident.
He was bought to shunt and pull goods, but then was transferred to the coastal run, on which he enjoys working. He is responsible for this line, which is famous for its fish. Arthur is the only known engine (with the exception of Salty and Porter) to enjoy the smell of fish.
Arthur is a big tank engine who has never been naughty in his life. He was highly esteemed for his "spotless record" before he arrived on Sodor, never having made a mess or a fuss and never having caused an accident. His main duties were to shunt trucks and haul goods trains. Arthur can be a bit naive however and after a jealous Thomas tricked Arthur into setting his standards too high with the trucks, his record did not stay as spotless as he had hoped. Arthur is very obedient, cautious, and well-behaved. He aims to please in his work and do everything as best he can. He now mainly runs the Fishing Route by the coastal village, a duty which Thomas was only all too grateful to be relieved from. Here, Arthur enjoys the sea air and the smell of the fish.
Arthur is an LMS Ivatt Class 2MT tank engine developed for the London Midland and Scottish Railway (hence the initials on his tanks). Unlike his basis, Arthur lacks a sandbox.
Arthur was numbered 41241 on his concept art. This Ivatt is still running today.
Arthur is painted LMS maroon with gold boiler bands and yellow lining and "LMS" written on his sides in yellow.
- Season 7 - Bill, Ben and Fergus (cameo), The Spotless Record, Something Fishy, Peace and Quiet (cameo), and Bulgy Rides Again (cameo)
- Season 8 - Fish
- Season 11 - Gordon and the Engineer (cameo) and Thomas and the Runaway Car
- Season 12 - Steady Eddie (does not speak)
- 2005 - Chimps' Playtime and Fresh Fish
- 2007 - Off to Market! and Mystery Tour
- 2008 - Left Alone (cameo)
- 2009 - King Arthur!
- 2011 - King Arthur!, Puffer Portrait, and Toby's Treat
- 2012 - Hooray for Henry (does not speak)
- Yasuhiro Takato (Japan; seventh and eighth seasons)
- Shinichirō Miki (Japan; eleventh season onwards)
- According to an early leak on the names of the seventh season characters, Arthur was originally going to be called Clarence. It was then changed to Arthur, when TV mag ran a competition to give him an official name, and that was the one chosen. Arthur was named after the late grandfather of competition winner Luke Sharp.
- Arthur was the only character in the twelfth season to have a role in an episode, but was never seen with a CGI face. Harvey technically did too, but he was seen with CGI faces in a few deleted scenes of said season.
- As of the ninth season learning segment, Arthur's Tricky Travels, Arthur has Edward's whistle.
- According to Robert Gauld-Galliers' original artwork, he was originally going to have the number 41241 painted in yellow on his coal bunker and a top feed like his original basis. The number 41241 comes from a preserved 2MT on the Keighley and Worth Valley Railway, and at one point, 41241 was painted in a maroon livery like Arthur.