Londonderry & Lough Swilly 4-8-4 Locomotives in Ireland

Class Details by Steve Llanso of Sweat House Media

Class 5 (Locobase 2691)

Data from "London & Lough Swilly Railway," The Locomotive, Volume 18, No (15 September 1912), p. 182. Works numbers were 985-986.

Later additions to the Lough Swilly, the extra driving axle providing useful traction and the total of eight axles spreading out the load. The locomotives had long Belpaire fireboxes that encompassed a sizable heating surface area.

Pride of the railway, these locomotives served first on the 49-mile (79 km) Letterkenny and Burtonport Railway extension as the heavy passenger haulers for much of their careers and helper service later. Both were scrapped in 1954.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID2691
RailroadLondonderry & Lough Swilly
Number in Class2
Road Numbers5-6
Number Built2
BuilderHudswell, Clarke
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.50 / 4.11
Engine Wheelbase (ft / m)31 / 9.45
Ratio of driving wheelbase to overall engine wheelbase 0.44
Overall Wheelbase (engine & tender) (ft / m)31 / 9.45
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)76,160 / 34,546
Engine Weight (lbs / kg)120,400 / 54,613
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)120,400 / 54,613
Tender Water Capacity (gals / ML)1800 / 6.82
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.80 / 3
Minimum weight of rail (calculated) (lb/yd / kg/m)32 / 16
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)45 / 1143
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)16" x 20" / 406x508
Tractive Effort (lbs / kg)17,408 / 7896.15
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.38
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)146 / 13.56
Grate Area (sq ft / m2)17.60 / 1.64
Evaporative Heating Surface (sq ft / m2)1063 / 98.76
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1063 / 98.76
Evaporative Heating Surface/Cylinder Volume228.40
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3168
Same as above plus superheater percentage3168
Same as above but substitute firebox area for grate area26,280
Power L15201
Power MT602.22

All material Copyright ©
Wes Barris