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South African class 21
In the late thirties A.G. Watson designed a heavy mixed-traffic locomotive that had to be limited to an axle load of 15 tons. As he had an aversion against articulated locomotives, it had to have five driving axles an...
| South African class 21Remove | |
|---|---|
| Variant | Standard |
| Built | 1937 |
| Manufacturers | North British |
| Wheel arrangement | 1E2 |
| Gauge | 1067 mm |
| Length | 23424 mm |
| Service mass | 108311 kg |
| Top speed | |
| Power | |
| Engine |
General
| Property | South African class 21 Standard Remove |
|---|---|
| Built | 1937 |
| Manufacturers | North British |
| Wheel arrangement | 2-10-4 (Texas) |
| Gauge | 1,067 mm |
Dimensions and weights
| Property | South African class 21 Standard Remove |
|---|---|
| Length | 23.42 m |
| Wheelbase | 11.20 m |
| Total wheelbase | 20.83 m |
| Service mass | 108.3 t |
| Adhesion mass | 74 t |
| Total mass | 175.2 t |
| Rigid wheelbase | 5.72 m |
| Axle load | 15.2 t |
| Water capacity | 25,400 l |
| Fuel capacity | 10.2 t (coal) |
Boiler
| Property | South African class 21 Standard Remove |
|---|---|
| Grate area | 5.853 m² |
| Firebox surface | 21.554 m² |
| Tube heating surface | 294.317 m² |
| Evaporative heating surface | 315.871 m² |
| Superheater surface | 62.803 m² |
| Total heating surface | 378.7 m² |
Power plant
| Property | South African class 21 Standard Remove |
|---|---|
| Driver diameter | 1,372 mm |
| Boiler pressure | 14.5 bar |
| Expansion type | simple expansion |
| Cylinders | two, 610 x 660 mm |
Power
| Property | South African class 21 Standard Remove |
|---|---|
| Power source | steam |
| Estimated power | 1,864 kW (2,534 PS) |
| Starting effort | 220.2 kN |
Calculated values
| Property | South African class 21 Standard Remove |
|---|---|
| Factor of adhesion | 1 : 3.30 |
| Optimal speed | 51 km/h |
| Power-to-weight ratio | 17.2 kW/t |
| Heating Surface Equivalent | 549.2 m² |
| Cylinder volume/HSE | 1 : 701.86 |
| Adhesive weight/Total | 1 : 1.46 |
| Tractive force/Heating surface | 1 : 12.15 |
| Grate area/Heating surface | 1 : 64.70 |
| Firebox/Tube surface | 1 : 13.65 |
| Total/Superheater | 1 : 5.03 |
