loco-info.com - Rhymney Railway class M

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.

General
Built	1904
Manufacturer	Robert Stephenson & Co.
Axle config	0-6-2T (Webb)
Gauge	4 ft 8 1/2 in (Standard gauge)

Dimensions and Weights
Length	36 ft 9 in
Wheelbase	21 ft 9 in
Rigid wheelbase	15 ft 3 in
Service weight	138,880 lbs
Water capacity	1,681 us gal
Fuel capacity	6,720 lbs (coal)

Boiler
Grate area	11.6 sq ft
Firebox area	122 sq ft
Tube heating area	1,252 sq ft
Evaporative heating area	1,374 sq ft
Total heating area	1,374 sq ft

Power Plant
Driver diameter	54 in
Boiler pressure	165 psi
Expansion type	simple
Cylinders	two, 18 1/2 x 26 in

Power
Power source	steam
Estimated power	450 hp (336 kW)
Starting effort	23,111 lbf

Calculated Values
Optimal speed	12 mph
Power-to-weight ratio	0.0032 hp/lb
Heating Area Equivalent	1,984 sq ft
Cylinder volume/HAE	1 : 1242.70
Tractive force/Heating area	1 : 3781.33
Grate area/Heating area	1 : 108.10
Firebox/Tube area	1 : 10.26

steam locomotive

tank locomotive

freight

Richard Jenkins

last changed: 05/2023

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