Smudger is a narrow-gauge tank engine who works on the Mid Sodor Railway.
According to Duke, Smudger was a showoff who rode roughly and often came off the rails. Duke tried to warn him to be careful, but Smudger never listened to his advice. He was finally punished by being turned into a generator and being put behind Arlesdale Sheds. Smudger was left there after the railway closed and remained there until he was discovered (along with Stanley) when they where repairing the railway to reopen it. Smudger was sent to the Sodor Steamworks and was turned back into an engine and now works on the Mid Sodor Railway again.