Great Western Railway class 2021
The GWR class 2021 was a 0-6-0 tank locomotive introduced in 1897. It was directly based on the class 850 of 1874, but had a longer wheelbase to fit a larger firebox. The design is generally being attributed to George Armstrong, but since he retired in 1897, the innovation to build the new class might also have come from this successor William Dean. Like the class 850, the class 2021 originally also had a saddle tank.
When Churchward wanted to fit a Belpaire firebox, due to its square profile, pannier tanks were the best choice. Most of the class was rebuilt in this way, but this process took until 1948 to be completed. By this time, British Railways took over 110 locomotives. Starting in 1949, the first ones were replaced by the class 1600 that was still based on the same design of 1874 and had dimensions which were very similar to the class 2021. In 1959, the last was withdrawn.
Technical data
General
- Built
- 1897-1905
- Manufacturers
- Wolverhampton
- Wheel arrangement
- 0-6-0ST (Six-coupled)
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Length
- 9.17 m
- Wheelbase
- 4.47 m
- Service mass
- 41.3 t
- Adhesion mass
- 41.3 t
- Rigid wheelbase
- 4.47 m
- Axle load
- 13.9 t
- Water capacity
- 4,546 l
Boiler
- Grate area
- 1.347 m²
- Firebox surface
- 8.594 m²
- Tube heating surface
- 86.052 m²
- Evaporative heating surface
- 94.645 m²
- Total heating surface
- 94.6 m²
Power plant
- Driver diameter
- 1,257 mm
- Boiler pressure
- 10.3 bar
- Expansion type
- simple expansion
- Cylinders
- two, 419 x 610 mm
Power
- Power source
- steam
- Estimated power
- 298 kW (405 PS)
- Starting effort
- 74.9 kN
Calculated values
- Factor of adhesion
- 1 : 5.42
- Optimal speed
- 24 km/h
- Power-to-weight ratio
- 7.2 kW/t
- Heating Surface Equivalent
- 137.6 m²
- Cylinder volume/HSE
- 1 : 1,222.17
- Adhesive weight/Total
- 1 : 1.00
- Tractive force/Heating surface
- 1 : 16.52
- Grate area/Heating surface
- 1 : 70.26
- Firebox/Tube surface
- 1 : 10.01
