The reference for locomotives and railcars
Rhymney Railway class M
Great Britain | 1904 | 6 produced
Railway Magazine, October 1905

The Class M was the first variant in a series of Rhymney Railway tank locomotives that led to the class 5600 of the GWR. It had been developed by Richard Jenkins and had three driving axles with relatively small wheels in order to achieve high tractive power for the heavy coal trains. Although some successor class P and A engines were later rebuilt to a similar level as the 5600, only one class M loco was so rebuilt. All came to the GWR in 1923 and British Railways received three in 1948, which were retired by 1951.

ManufacturerRobert Stephenson & Co.
Axle config0-6-2T (Webb) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length36 ft 9 in
Wheelbase21 ft 9 in
Fixed wheelbase15 ft 3 in
Service weight138,880 lbs
Water capacity1,681 us gal
Fuel capacity6,720 lbs (coal)
Power sourcesteam
Estimated power450 hp (336 kW)
Optimal speed12 mph
Starting effort23,111 lbf
Power Plant
Driver diameter54 in
Boiler pressure165 psi
Expansion typesimple
Cylinderstwo, 18 1/2 x 26 in
Grate area11.6 sq ft
Firebox area122 sq ft
Tube heating area1,252 sq ft
Evaporative heating area1,374 sq ft
Total heating area1,374 sq ft
Calculated Values
steam locomotive
tank locomotive
Richard Jenkins
last changed: 05/2023

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