Banner
Navigation

Navigation

loco-info.com
The reference for locomotives and railcars

London & South Western class L12 “Bulldogs”

Great Britain 1904 20 produced
PD

The GWR and the LSWR 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 tubes 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 However, 421 was repaired and all 20 class members survived until the formation of British Railways. 18 were withdrawn in 1951 and the last two in 1953 and 1955 respectively.

Technical data

General

Property as built superheated
Built 1904-1905
Manufacturers Nine Elms
Wheel arrangement 4-4-0 (American)
Gauge 1,435 mm (Standard gauge)

Dimensions and weights

Property as built superheated
Length 19.43 m
Wheelbase 7.09 m
Service mass 54.8 t 54.1 t
Adhesion mass 37.7 t 35.7 t
Total mass 100.3 t 99.6 t
Rigid wheelbase 3.05 m
Axle load 19.4 t 18.5 t
Water capacity 21,823 l
Fuel capacity 4.5 t (coal)

Boiler

Property as built superheated
Grate area 2.23 m²
Firebox surface 30.472 m² 18.116 m²
Tube heating surface 113.528 m² 92.253 m²
Evaporative heating surface 144 m² 110.369 m²
Total heating surface 144.0 m² 128.5 m²
Superheater surface 18.116 m²

Power plant

Property as built superheated
Driver diameter 2,007 mm
Boiler pressure 12.1 bar
Expansion type simple expansion
Cylinders two, 483 x 660 mm

Power

Property as built superheated
Power source steam
Estimated power 597 kW (812 PS) 820 kW (1,115 PS)
Starting effort 78.6 kN

Calculated values

Property as built superheated
Factor of adhesion 1 : 4.70 1 : 4.45
Optimal speed 47 km/h 64 km/h
Power-to-weight ratio 10.9 kW/t 15.2 kW/t
Heating Surface Equivalent 296.4 m² 237.2 m²
Cylinder volume/HSE 1 : 815.23 1 : 1,018.64
Adhesive weight/Total 1 : 1.45 1 : 1.52
Tractive force/Heating surface 1 : 11.40 1 : 12.78
Grate area/Heating surface 1 : 64.57 1 : 57.62
Firebox/Tube surface 1 : 3.73 1 : 5.09
Total/Superheater 1 : 6.09
Auf Deutsch umschalten

Settings

Your settings are retained for this browser session only.

Consent to cookies

We use cookies to save your display settings. If you decline, the settings are retained only for the current browser session.