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London & South Western class L12 “Bulldogs”
Great Britain | 1904 | 20 produced
flickr/Historical Railway Images

The GWR and the LNWR were in direct competition for boat trains, i.e. the heavy non-stop express trains between London and the ports on the Channel coast. In light of the new GWR 4-4-0 locos such as the City Class, Dugald Drummond developed the L12 as a successor to the T9 “Greyhound”. Both were similar in many respects, including the diameter of the driving wheels, cylinder dimensions, boiler pressure and the water tubes in the firebox

With the boiler being shorter and thicker than that of the T9, they earned the nickname “Bulldogs”. Since the changes compared to the previous class were limited, they did not represent any particular improvement. The L12 also had a four-axle tender again in order to be able to run the line without stopping. Later, under Urie, they received a new boiler with a superheater that no longer had water pipes in the firebox

The class made negative headlines as early as 1906 when number 421 derailed with a boat train in Salisbury, killing 28 and injuring 11 others. The accident is generally attributed to the L12's higher center of gravity, although other locos would also probably have derailed at 70 mph while negotiating a 30 mph curve. From this point on, the competition between the two companies became less intense. However, the 421 was refurbished and all 20 examples survived until the formation of British Railways. 18 were retired in 1951 and the last two in 1953 and 1955 respectively.

Variantas builtsuperheated
ManufacturerNine Elms
Axle config4-4-0 (American) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length63 ft 9 in
Wheelbase23 ft 3 in
Fixed wheelbase10 ft
Service weight120,848 lbs119,169 lbs
Adhesive weight83,104 lbs78,623 lbs
Total weight221,200 lbs219,631 lbs
Axle load42,784 lbs40,768 lbs
Water capacity5,765 us gal
Fuel capacity9,856 lbs (coal)
Power sourcesteam
Estimated power800 hp (597 kW)1,100 hp (820 kW)
Optimal speed29 mph40 mph
Starting effort17,673 lbf
Power Plant
Driver diameter79 in
Boiler pressure175 psi
Expansion typesimple
Cylinderstwo, 19 x 26 in
Grate area24 sq ft
Firebox area328 sq ft195 sq ft
Tube heating area1,222 sq ft993 sq ft
Evaporative heating area1,550 sq ft1,188 sq ft
Superheater area195 sq ft
Total heating area1,550 sq ft1,383 sq ft
Calculated Values
steam locomotive
Dugald Drummond
last changed: 07/2022

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