War Department Light Railways 2-6-2 Locomotives in Great_Britain


Class Details by Steve Llanso of Sweat House Media

Class Trench loco (Locobase 5043)

One of several narrow-gauge designs built for war service during World War I. Data from Bruce (1952) and from WJK Davies Light Railways of the First World War (NY;Reprints of Economic Classics, 1968).

Davies notes that these were the most powerful steam locomotives on the light railways. They were well-liked because of both that power and of their double-ender running. He adds that after the war, a number of these Alcos ran on French lines. One in particular was the Tramway de Pithwies a' Towy, which operated three of these obviously durable engines until it closed in 1964.

Principal Dimensions by Steve Llanso of Sweat House Media

ClassTrench loco
Locobase ID5043
RailroadWar Department Light Railways
CountryGreat Britain
Whyte2-6-2T
Number in Class100
Road Numbers1207-1300
Gauge60 cm
Number Built100
BuilderAlco-Cooke
Year1917
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m) 5.50 / 1.68
Engine Wheelbase (ft / m)16.50 / 5.03
Ratio of driving wheelbase to overall engine wheelbase 0.33
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)8036 / 3645
Weight on Drivers (lbs / kg)23,772 / 10,783
Engine Weight (lbs / kg)38,500 / 17,463
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)38,500 / 17,463
Tender Water Capacity (gals / ML)475 / 1.80
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)13 / 6.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)27 / 686
Boiler Pressure (psi / kPa)175 / 12.10
High Pressure Cylinders (dia x stroke) (in / mm)9" x 14" / 229x356
Tractive Effort (lbs / kg)6248 / 2834.05
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.80
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 8.50 / 2.59
Firebox Area (sq ft / m2)
Grate Area (sq ft / m2) 5.40 / 0.50
Evaporative Heating Surface (sq ft / m2)264 / 24.54
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)264 / 24.54
Evaporative Heating Surface/Cylinder Volume256.10
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation945
Same as above plus superheater percentage945
Same as above but substitute firebox area for grate area
Power L1
Power MT

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