County Donegal class 4
Ireland 1904 4 produced
The Railways Joint Committee for County Donegal procured four tank locomotives to cope with the increasing weight of freight trains. With seven axles and a mass of nearly 45 tons, they were a substantial size for the three-foot gauge.
According to reports, the boiler originally had a poor steaming performance, which was attributed to an excessive number of heating tubes. Performance improved with the removal of the top row of tubes. In the 1920s, they were all fitted with a superheater, which again significantly increased performance.
The four locomotives were numbered 12 to 15 and named “Eske”, “Owenea”, “Erne” and “Mourne”. Three locomotives were scrapped in 1952 and 1954, but the “Erne” survived until 1968.
Technical data
General
- Built
- 1904
- Manufacturers
- Nasmyth, Wilson & Co.
- Wheel arrangement
- 4-6-4T (Hudson)
- Gauge
- 914 mm (Three feet)
Dimensions and weights
- Wheelbase
- 7.67 m
- Service mass
- 45.2 t
- Adhesion mass
- 26.4 t
- Rigid wheelbase
- 2.74 m
- Axle load
- 8.8 t
- Water capacity
- 6,818 l
- Fuel capacity
- 2.7 t (coal)
Boiler
- Grate area
- 1.115 m²
- Firebox surface
- 7.432 m²
- Tube heating surface
- 59.737 m²
- Evaporative heating surface
- 67.169 m²
- Total heating surface
- 67.2 m²
Power plant
- Driver diameter
- 1,143 mm
- Boiler pressure
- 11 bar
- Expansion type
- simple expansion
- Cylinders
- two, 381 x 533 mm
Power
- Power source
- steam
- Estimated power
- 261 kW (355 PS)
- Starting effort
- 63.5 kN
Calculated values
- Factor of adhesion
- 1 : 4.08
- Optimal speed
- 26 km/h
- Power-to-weight ratio
- 5.8 kW/t
- Heating Surface Equivalent
- 104.3 m²
- Cylinder volume/HSE
- 1 : 1,165.78
- Adhesive weight/Total
- 1 : 1.71
- Tractive force/Heating surface
- 1 : 19.75
- Grate area/Heating surface
- 1 : 60.24
- Firebox/Tube surface
- 1 : 8.04
