| Powertype: | Steam |
| NER Class R LNER Class D20 | |
| Designer: | Wilson Worsdell |
| Boiler: | 4inchesft9inchesin (ftin) diameter |
| Builder: | NER Gateshead |
| Builddate: | 1899-1907 |
| Totalproduction: | 60 |
| Whytetype: | 4-4-0 |
| Leadingdiameter: | 4feet |
| Driverdiameter: | 6feet |
| Wheelbase: | 23inchesft9inchesin (ftin) engine 12inchesft8inchesin (ftin) tender 45inchesftNaNinchesin (ftin) total |
| Locoweight: | D20/1: 54.1LT D20/2: 55.45LT |
| Tenderweight: | 41.2LT |
| Locotenderweight: | D20/1: 95.3LT D20/1: 96.65LT |
| Axleload: | 19.8LT |
| Cylindercount: | two inside |
| Cylindersize: | 19x |
| Boilerpressure: | 200psi later reduced to 160psi |
| Totalsurface: | 1318.7square feet |
| Firearea: | 20square feet |
| Fireboxarea: | 139square feet |
| Tubearea: | 638.7square feet |
| Fluearea: | 292square feet |
| Superheaterarea: | 204square feet |
| Tractiveeffort: | 17025lbf later reduced to 15567lbf |
| Valvegear: | Stephenson |
| Operator: | North Eastern Railway, London and North Eastern Railway, British Railways |
| Powerclass: | BR: 2P |
| Retiredate: | 1943-1957 |
| Disposition: | All scrapped |
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.
Forty-six D20/1 and three D20/2 locomotives passed to British Railways in 1948 and they were numbered 62340-62397 (with gaps).
The last D20 was withdrawn in 1957 and none were preserved.