With the formation of British Railways on 1 January 1948, the British Transport Commission took over. As the member for Mechanical and Electrical Engineering in the Railways Executive, Robert Riddles gathered a group of staff to plan, design and construct a group of 12 locomotive types to be 'Standard' classes. These became the new workhorses of British Railways, replacing many older classes whilst at the same time working alongside those classes from the 'Big Four' that had already proved themselves reliable. Designed to allow easy access for both daily maintenance and daily running needs, they were all equipped with Belpaire fireboxes, rocking grates, self-emptying ash pans and self-cleaning smoke boxes. A total of 999 were constructed over 10 years from 1951-1960, ranging from a Class 7 4-6-2, Britannia, to a Class 9 2-10-0 heavy goods locomotive, the last of which entered service in March 1960, given the name Evening Star.