North Eastern class D
London & North Eastern class H1
The North Eastern Railway's class D was developed by Vincent Raven for rural passenger trains. In order to achieve equally good running characteristics in both directions of travel, he chose a tank locomotive with a 4-4-4T wheel arrangement. Three cylinders ensured smoother acceleration. Although there were only two axles available for traction, the coefficient of adhesion of more than four indicated that there was enough traction for starting without slipping.
The first 20 were built in Darlington in 1913. Another 25 followed after the war in the years 1920 to 1922. The LNER took over the locomotives as class H1. Between 1931 and 1936, all were rebuilt to a 4-6-2T wheel arrangement. These were designated class A8 and were retired between 1957 and 1960.
Technical data
General
- Built
- 1913, 1920-1922
- Manufacturers
- Darlington
- Wheel arrangement
- 4-4-4T (Reading)
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Wheelbase
- 10.52 m
- Service mass
- 86.1 t
- Adhesion mass
- 40.4 t
- Rigid wheelbase
- 2.44 m
- Axle load
- 20.2 t
- Water capacity
- 9,093 l
- Fuel capacity
- 4.1 t (coal)
Boiler
- Grate area
- 2.137 m²
- Firebox surface
- 11.52 m²
- Tube heating surface
- 86.864 m²
- Evaporative heating surface
- 98.384 m²
- Superheater surface
- 25.363 m²
- Total heating surface
- 123.7 m²
Power plant
- Driver diameter
- 1,753 mm
- Boiler pressure
- 11 bar
- Expansion type
- simple expansion
- Cylinders
- three, 419 x 660 mm
Power
- Power source
- steam
- Estimated power
- 634 kW (862 PS)
- Starting effort
- 93.1 kN
Calculated values
- Factor of adhesion
- 1 : 4.26
- Optimal speed
- 42 km/h
- Power-to-weight ratio
- 7.4 kW/t
- Heating Surface Equivalent
- 206.7 m²
- Cylinder volume/HSE
- 1 : 1,322.18
- Adhesive weight/Total
- 1 : 2.13
- Tractive force/Heating surface
- 1 : 15.71
- Grate area/Heating surface
- 1 : 57.91
- Firebox/Tube surface
- 1 : 7.54
- Total/Superheater
- 1 : 3.88
