zGWR Caldicot Castle Big 4 CenHOR R30272 Hornby GWR, Castle Class, 4 6 0, 4074 'Caldicot Castle': Big Four Centenary Collection Era 3 2023 Catalogue The Castle Class was designed by Charles Collett, the successor to legendary GWR engineer George Jackson Churchward. In truth, Castle Class is nothing more than a nickname owing to most examples of the class being named after western castles with the official GWR designation being the 4073 class. This name comes from the first example