High Quality Content by WIKIPEDIA articles! The NER Class R (later, LNER Class D20) was a class of 4-4-0 steam locomotive, designed by Wilson Worsdell for the North Eastern Railway. They passed to the London and North Eastern Railway (LNER) in 1923. In 1936, some were rebuilt with long-travel piston valves and classified D20/2. The unrebuilt locomotives were re-classified D20/1.