Stock Photo - BR Standard Class 7 Steam Locomotive number 70000 â. œ Britannia â. œ at Alresford Station on the Mid Hants Railway during the railwayâ. . s Spring Steam Gala on the 13th February 2014 . . The BR Standard Class 7, otherwise known as the Britannia Class, is a class of 4-6-2 Pacific steam locomotive designed by Robert Riddles for use by British Railways for mixed traffic duties. Fifty-five were constructed between 1951 and 1954. The Britannia Class was based on several previous locomotive designs, incorporating the best practices in locomotive technology as regards labour-saving and lowering maintenance costs; . The Britannias took their names from great Britons, The class remained in service until the last was withdrawn in 1968. Only two of the class survive . Number 70000 was returned to the main line in 2011. and has hauled several mainline excursions. The Mid Hants Heritage Railway also known as â. œ The Watercress Line â. œ ( due to watercress production in the area ) running 10 miles (16 km) in Hampshire Southern England from New Alresford to Alton where it connects to the National Rail network.