What is NER Class R?
{{Infobox locomotive |powertype=Steam |name = NER Class R <br> LNER Class D20 |image = Gateshead Locomotive Depot geograph-2327896-by-Ben-Brooksbank.jpg |caption = 1907-built class R 2387, at Gateshead in 1954 |designer = [[Wilson Worsdell]] |boiler = {{convert|4|ft|9|in|abbr=on}} diameter |builder = NER [[Gateshead works|Gateshead]] |builddate = 1899-1907 |totalproduction = 60 |whytetype = [[4-4-0]] |gauge = {{Track gauge|uksg|allk=on}} |leadingdiameter = {{convert|4|ft|0|in|3|abbr=on}} |driverdiameter = {{convert|6|ft|10|in|3|abbr=on}} |length = |wheelbase = {{convert|23|ft|9|in|abbr=on}} engine <br> {{convert|12|ft|8|in|abbr=on}} tender <br> {{convert|45|ft|10+3/4|in|abbr=on}} total |locoweight = D20/1: {{convert|54.1|LT|t ST|abbr=on}} <br> D20/2: {{convert|55.45|LT|t ST|abbr=on}} |tenderweight = {{convert|41.2|LT|t ST|abbr=on}} |locotenderweight = D20/1: {{convert|95.3|LT|abbr=on}} <br> D20/1: {{convert|96.65|LT|t ST|abbr=on}} |axleload = {{convert|19.8|LT|t ST|abbr=on}} |fueltype = [[Coal]] |fuelcap = |watercap = |cylindercount = two inside |cylindersize = {{convert|19|x|26|in|0|abbr=on}} |boilerpressure = {{convert|200|psi|MPa|abbr=on}} <br> later reduced to {{convert|160|psi|MPa|abbr=on}} |totalsurface = {{convert|1318.7|sqft|abbr=on}} |firearea = {{convert|20|sqft|abbr=on}} |fireboxarea = {{convert|139|sqft|abbr=on}} |tubearea = {{convert|638.7|sqft|abbr=on}} |fluearea = {{convert|292|sqft|abbr=on}} |superheaterarea = {{convert|204|sqft|abbr=on}} |tractiveeffort = {{convert|17025|lbf|kN|abbr=on}} <br> later reduced to {{convert|15567|lbf|kN|abbr=on}} |valvegear = [[Stephenson valve gear|Stephenson]] |operator = [[North Eastern Railway (UK)|North Eastern Railway]], [[London and North Eastern Railway]], [[British Railways]] |powerclass = BR: 2P |operatorclass= |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 (UK)|North Eastern Railway]].