Alfred and Crovan are two blue tender engines who had visited Sodor in 1922.
When the Reverend W. Awdry received correspondence asking about the two blue engines in the shed - the other four being Edward, Henry, Gordon, and the Red Engine - he replied that they were sent to the railway on trial, but were sent away for being rude and nasty. It is unknown what happened to them since the decline of steam, but they were most likely scrapped.
Alfred and Crovan are rude, spiteful, impolite, disrespectful and nasty.
It is unknown what type of engine Alfred and Crovan really are. Alfred looks like a cross between Edward and Gordon with a 4-6-0 wheel arrangement, no outside cylinders or motion, Stephenson valve gear and oval buffers; Crovan looks a cross between Gordon and Henry in his old shape with a 4-6-0 wheel arrangement, two-cylinder motion, Walschaerts valve gear and round buffers. Some have theorised that Alfred is an LNER B12 and Crovan is an LNER B17. However, B17s were not built until 1928. Although he does resemble an LNER B1 or B16.
Alfred and Crovan are painted blue with red and yellow lining.