South African class NG G13
The NG G13 was created as the successor to the NG G11 for the two-foot narrow-gauge network. It was significantly enlarged compared to its predecessor and was given an inner carrying axle on each bogie, leading to the 2-6-2+2-6-2T wheel arrangement. While the outer carrying axles were designed as radially adjustable Adams axles, the carrying axles could only be moved laterally with the Gölsdorf system.
Since the South African government had much better contacts with Germany than with Great Britain at the time, the twelve locomotives were ordered from Hanomag. At the time of their commissioning, they were the heaviest locomotives in the world built for a gauge of two feet. With the NG G13, the train weights on the narrow-gauge lines could be significantly increased, which even made it unnecessary to convert some lines to Cape gauge. In Natal, it was used successfully on lines with curve radii of 148 feet and a gradient of 1 in 33.
One of the negative points of the locomotives was that the cab was too small, in which the heat accumulated due to several devices. The crews therefore apparently took advantage of the movable stools and often leaned out of the doors while exploiting the locomotive's capabilities. The withdrawals took place in quick succession in 1973 after the introduction of the class 91-000 diesel locomotives. Three are still operational today, one at the Sandstone Estates in South Africa, one on the Vale of Rheidol Railway in Wales and one on the Hempstead and Northern Railroad in Texas. All but two of the rest still exist today, but some are in a scrap condition.
Technical data
General
- Built
- 1927-1928
- Manufacturers
- Hanomag
- Wheel arrangement
- 2-6-2+2-6-2T (Double Prairie (Garratt))
- Gauge
- 610 mm (Two feet)
Dimensions and weights
- Length
- 14.76 m
- Wheelbase
- 4.01 m
- Total wheelbase
- 13.03 m
- Service mass
- 62.7 t
- Adhesion mass
- 41.7 t
- Rigid wheelbase
- 1.91 m
- Axle load
- 7.2 t
- Water capacity
- 8,298 l
- Fuel capacity
- 4.1 t (coal)
Boiler
- Grate area
- 1.812 m²
- Firebox surface
- 7.627 m²
- Tube heating surface
- 77.936 m²
- Evaporative heating surface
- 85.564 m²
- Superheater surface
- 13.843 m²
- Total heating surface
- 99.4 m²
Power plant
- Driver diameter
- 838 mm
- Boiler pressure
- 12.4 bar
- Expansion type
- simple expansion
- Cylinders
- four, 305 x 406 mm
Power
- Power source
- steam
- Estimated power
- 522 kW (710 PS)
- Top speed
- 40 km/h
- Starting effort
- 95.0 kN
Calculated values
- Factor of adhesion
- 1 : 4.31
- Optimal speed
- 34 km/h
- Power-to-weight ratio
- 8.3 kW/t
- Heating Surface Equivalent
- 151.4 m²
- Cylinder volume/HSE
- 1 : 783.53
- Adhesive weight/Total
- 1 : 1.50
- Tractive force/Heating surface
- 1 : 19.97
- Grate area/Heating surface
- 1 : 54.86
- Firebox/Tube surface
- 1 : 10.22
- Total/Superheater
- 1 : 6.18