Medea was initially constructed as an enlarged version of Talos, but with an 0-6-2T wheel arrangement, 8½″ driving wheels, D shaped smokebox, and a fully enclosed cab. Medea also retained the concept of a marine boiler and Heywood valve gear.
When completed in 1981, the loco was soon converted to a 2-6-2T by fitting an extra set of pony wheels to the front and extending the front running plate. This provided better weight distribution, with the front wheels helping to guide the loco and reducing wear on the outer rail, ultimately providing a smoother ride.
A locomotive type boiler replaced the marine boiler in 1985 which made the loco more suitable for intensive operation at Tucktonia.
More recently, Medea had a full rebuild including the fitting of 3½″ bore cylinders but retaining the Heywood valve gear.
Medea has always carried the LB&SCR Umber livery with the name painted in gold lettering on the side tanks.
