SAR class GG
| SAR class GG | |
|---|---|
_b.jpg) GG No. 2290 in Cape Town , ca.1930
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| Numbering: | 2290 |
| Number: | 1 |
| Manufacturer: | Beyer-Peacock |
| Year of construction (s): | 1925 |
| Retirement: | 1938 |
| Type : | (1'C1 ') (1'C1') h4 (Garratt) |
| Gauge : | 1067 mm ( cape track ) |
| Service mass: | 150 t |
| Friction mass: | 96 t |
| Wheel set mass : | 16.4 t |
| Driving wheel diameter: | 1447 mm |
| Impeller diameter: | k. A. |
| Cylinder diameter: | 457 mm |
| Piston stroke: | 660 mm |
| Boiler overpressure: | 124.1 N / cm² |
| Grate area: | 4.83 m² |
| Radiant heating surface: | 19.51 m² |
| Tubular heating surface: | 219.8 m² |
| Superheater area : | 36.2 m² |
| Train brake: | Suction air brake |
The unique piece of the GG class of the South African Railways (SAR) was a Garratt steam locomotive .
The GG class was developed together with the GE class and was based on the same boiler, which in turn largely corresponded to that of the GA class . While the GE class had the axle sequence (1'D1 ') (1'D1'), the GG class had larger drive wheels and the axle sequence (1'C1 ') (1'C1'). With almost the same total weight, the axle load was almost three tons higher, so that the locomotive was faster, but could only be used on main lines.
The locomotive with the number 2290 delivered by Beyer-Peacock in 1925 was used in front of mail trains from Cape Town over the Hex River Pass , which has gradients of up to 25 ‰. In a test drive, an average of 76.6 km / h was achieved on a 15.5 km long route from departure to stop, with the maximum speed being 92 km / h.
However, since the cylinder diameter of class GG was not increased compared to that of class GE in order to compensate for the larger drive wheel diameter, the pulling force was lower. For this reason, the locomotive proved to be inferior to the class 15CA (wheel arrangement 2'D1 ') with four coupled locomotives introduced a little later on the same route , so that the type was no longer procured.
The locomotive was scrapped as a single piece as early as 1938, with the boiler still being used for the maintenance of the GE class.
literature
- AE Durrant: Garratt locomotives of the world. Birkhäuser, Basel et al. 1984, ISBN 3-7643-1481-8 .
