Developed by Wilson Worsdell, the Class R was a 4-4-0 with larger dimensions than had previously been the norm for this wheel arrangement in Britain. From 1899 30 were built and another 30 in 1906 and 1907. During World War I they were rebuilt with a superheater. At the LNER they became the D20. After some received new piston valves in 1936, the rebuilt ones became the D20/2 class and the remainder the D20/1. The British Railways received 49 of the original 60 locomotives, these disappeared by 1957. ![](./images/status_hasBaseData.png)