For years B.R. ran an excursion, weekly, to the seaside resort of Skegness, using the ancient class 20s. these became so popular with enthusiasts that they were taken off! Well, I can't think of any other reason - the locos are still running! the locos run back-to-back because they only have a cab at one end, and being class 1 locos, two are needed for the load.