NER Class M1

{{Use dmy dates|date=August 2017}}

{{Use British English|date=August 2017}}

{{inline|date=June 2014}}

{{infobox locomotive

|name = NER Class M1/M, Q and Q1
LNER Class D17/1, D17/2 and D18

|powertype = Steam

|image = North Eastern Railway Class M1 no. 1621 (6684770383).jpg

|caption = Preserved M1 No. 1621 in the National Railway Museum, York, September 2010

|designer = Wilson Worsdell

|builder = NER Gateshead

|builddate = 1892-1894 (Class M1)
1896-1897 (Class Q)
1896 (Class Q1)

|totalproduction = 20 (Class M1)
30 (Class Q)
2 (Class Q1)

|whytetype = 4-4-0

|uicclass = 2′B n2

|gauge = {{RailGauge|uksg}}

|length = Q1 {{convert|17.145|m|ft|abbr=on}}

|leadingdiameter = {{convert|3|ft|7+1/4|in|mm|0|abbr=on}}

|driverdiameter = {{convert|7|ft|1+1/4|in|mm|0|abbr=on}}

|wheelbase = {{convert|23|ft|6|in|m|2|abbr=on}} Class M1/Q engine
{{convert|23|ft|9|in|m|2|abbr=on}} Class Q1 engine
{{convert|12|ft|8|in|abbr=on}} tender
{{convert|45|ft|8+1/4|in|abbr=on}} Class M1/Q total
{{convert|46|ft|2+3/4|in|abbr=on}} Class Q1 total

|axleload = M1: {{convert|18.6|LT|abbr=on}}
Q: {{convert|18.8|LT|abbr=on}}
Q1: {{convert|19.2|LT|abbr=on}}

|locoweight = {{convert|52.5|LT|abbr=on}} (Class M1)
{{convert|50.3|LT|abbr=on}} (Class Q)
{{convert|53.5|LT|abbr=on}} (Class Q1)

|tenderweight = {{convert|41.2|LT|abbr=on}}

|locotenderweight= {{convert|93.7|LT|abbr=on}} (Class M1)
{{convert|91.5|LT|abbr=on}} (Class Q)
{{convert|94.7|LT|abbr=on}} (Class Q1)

|fueltype = Coal

|fuelcap =

|watercap = {{convert|4125|impgal|abbr=on}}

|boiler = {{convert|4|ft|4|in|m|2|abbr=on}} diameter

|boilerpressure = {{convert|160|psi|MPa|2|abbr=on}}

|firearea = {{convert|19.8|sqft|abbr=on}}

|tubearea = {{convert|479|sqft|abbr=on}}

|fluearea = {{convert|291|sqft|abbr=on}}

|fireboxarea = {{convert|123|sqft|abbr=on}}

|totalsurface = {{convert|1097|sqft|abbr=on}}

|superheaterarea = {{convert|204|sqft|abbr=on}}

|cylindercount = Two, inside

|cylindersize = {{convert|19|x|26|in|mm|0|abbr=on}}
{{convert|20|x|26|in|mm|0|abbr=on}} (No. 1870)

|valvegear = Stephenson

|tractiveeffort = {{convert|14974|lbf|kN|2|abbr=on}} (Class M1/Q)
{{convert|13990|lbf|kN|2|abbr=on}} (No. 1869)
{{convert|15500|lbf|kN|abbr=on}} (No. 1870)

|operator = North Eastern Railway, London & North Eastern Railway, British Rail

|withdrawndate = 1931–1945 (Class M1)
1931–1948 (Class Q)
1930 (Class Q1)

|disposition = One M1 preserved (No. 1621); remainder M1, Q & Q1 scrapped

}}

The North Eastern Railway Class M1 (LNER Class D17/1) is a class of 4-4-0 steam locomotive, designed by Wilson Worsdell. 20 initial engines were built, then 30 further units were built, designated Class Q (LNER Class D17/2).