London & North Eastern class A8
Great Britain 1931 45 produced
The class A8 of the LNER was created when Gresley rebuilt all 45 locomotives of the North Eastern class D, the later LNER class H1 that had been designed by Vincent Raven. To make this 4-4-4T better suited for heavy suburban traffic and long distance coastal trains, he swapped the two-axle trailing bogie against a single axle and added another driving axle, making it a 4-6-2T.
In this process, also the boiler was revised. It was now operated with 175 instead of 160 psi and had a Robinson superheater instead of the Schmidt type. After all had been rebuilt between 1931 and 1936, they also replaced the 0-4-4T class G5. The introduction of the DMUs in the 1950s was the decline of the A8. They were withdrawn between 1957 and 1960.
Technical data
General
- Built
- 1931-1936
- Manufacturers
- Gateshead
- Wheel arrangement
- 4-6-2T (Pacific)
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Length
- 12.95 m
- Wheelbase
- 10.14 m
- Service mass
- 88.2 t
- Adhesion mass
- 54 t
- Axle load
- 18.1 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
- 89.28 m²
- Evaporative heating surface
- 100.8 m²
- Superheater surface
- 17.744 m²
- Total heating surface
- 118.5 m²
Power plant
- Driver diameter
- 1,753 mm
- Boiler pressure
- 12.1 bar
- Expansion type
- simple expansion
- Cylinders
- three, 419 x 660 mm
Power
- Power source
- steam
- Estimated power
- 727 kW (988 PS)
- Starting effort
- 101.8 kN
Calculated values
- Factor of adhesion
- 1 : 5.20
- Optimal speed
- 43 km/h
- Power-to-weight ratio
- 8.2 kW/t
- Heating Surface Equivalent
- 193.9 m²
- Cylinder volume/HSE
- 1 : 1,409.62
- Adhesive weight/Total
- 1 : 1.63
- Tractive force/Heating surface
- 1 : 17.94
- Grate area/Heating surface
- 1 : 55.47
- Firebox/Tube surface
- 1 : 7.75
- Total/Superheater
- 1 : 5.68
