Great Western Railway class 1000 “County”
The County class of the GWR was developed by Hawksworth during World War II and was intended for mixed service. It was the last of a series of ten-wheelers begun by Churchward in 1902 with the Saint class. It included some innovations such as 280 psi boiler pressure and dual chimneys. However, the pressure was later reduced to 250 psi to save on maintenance costs, and later examples had single chimneys. Special optical features for GWR locomotives were the continuous splashers over all driving axles and straight nameplates.
After two batches and 30 locomotives, production was discontinued as the staff evidently preferred the locomotives from Hawksworth's predecessor, Collett, and there was no need for more. The County class was retired between 1962 and 1964. Although not a single locomotive has survived, number 1014 “County of Glamorgan” is currently being built new.
Technical data
General
| Property | as built | reduced boiler pressure |
|---|---|---|
| Built | 1945-1947 | |
| Manufacturers | Swindon | |
| Wheel arrangement | 4-6-0 (Ten-wheeler) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | reduced boiler pressure |
|---|---|---|
| Length | 19.21 m | |
| Wheelbase | 8.31 m | |
| Service mass | 78.1 t | |
| Adhesion mass | 60 t | |
| Total mass | 127.9 t | |
| Rigid wheelbase | 4.50 m | |
| Axle load | 20 t | |
| Water capacity | 18,185 l | |
| Fuel capacity | 7.1 t (coal) | |
Boiler
| Property | as built | reduced boiler pressure |
|---|---|---|
| Grate area | 2.679 m² | |
| Firebox surface | 15.701 m² | |
| Tube heating surface | 143.535 m² | |
| Evaporative heating surface | 159.236 m² | |
| Superheater surface | 23.597 m² | |
| Total heating surface | 182.8 m² | |
Power plant
| Property | as built | reduced boiler pressure |
|---|---|---|
| Driver diameter | 1,905 mm | |
| Boiler pressure | 19.3 bar | 17.2 bar |
| Expansion type | simple expansion | |
| Cylinders | two, 470 x 762 mm | |
Power
| Property | as built | reduced boiler pressure |
|---|---|---|
| Power source | steam | |
| Estimated power | 1,715 kW (2,332 PS) | 1,603 kW (2,179 PS) |
| Starting effort | 144.9 kN | 129.4 kN |
Calculated values
| Property | as built | reduced boiler pressure |
|---|---|---|
| Factor of adhesion | 1 : 4.06 | 1 : 4.55 |
| Optimal speed | 72 km/h | 76 km/h |
| Power-to-weight ratio | 22.0 kW/t | 20.5 kW/t |
| Heating Surface Equivalent | 284.9 m² | |
| Cylinder volume/HSE | 1 : 927.56 | |
| Adhesive weight/Total | 1 : 1.30 | |
| Tractive force/Heating surface | 1 : 16.56 | 1 : 14.78 |
| Grate area/Heating surface | 1 : 68.25 | |
| Firebox/Tube surface | 1 : 9.14 | |
| Total/Superheater | 1 : 6.75 | |