SAR class GH
| SAR class GH | |
|---|---|
.jpg) SAR class GH
|
|
| Numbering: | 2320-2321 |
| Number: | 2 |
| Manufacturer: | Maffei |
| Year of construction (s): | 1927 |
| Retirement: | 1957 |
| Type : | (2'C1 ') (1'C2') h4 |
| Gauge : | 1067 mm ( cape track ) |
| Length over coupling: | 25,906 mm |
| Service mass: | 187.7 t |
| Friction mass: | 109.2 t |
| Wheel set mass : | 18.4 t |
| Driving wheel diameter: | 1,524 mm |
| Impeller diameter: | 762 mm |
| Cylinder diameter: | 495 mm |
| Piston stroke: | 660 mm |
| Boiler overpressure: | 124.1 N / cm² |
| Grate area: | 5.53 m² |
| Radiant heating surface: | 22.23 m² |
| Tubular heating surface: | 223.2 m² |
| Superheater area : | 59.5 m² |
| Train brake: | Suction air brake |
The vehicles of the class GH of the South African Railways (SAR) were articulated locomotives of the type Union-Garratt .
In contrast to real Garratts , these locomotives were a hybrid of Garratt and Modified Fairlie : the front water tank was built on the front bogie like a Garratt, while the coal box, like a Modified Fairlie, was mounted on the bridge frame, which also carried the boiler and driver's cab . A second water tank was hung under the boiler frame.
Two pieces were delivered by Maffei in 1927; at that time they were the heaviest locomotives ever built in Europe. In the same year Maffei also supplied the ten-Union Garratts the Class U . Why the one type with the designation "GH" was classified as a real Garratt and the other with "U" as Union Garratt is no longer understandable today.
The class GH locomotives were intended for express train service on main lines and had the wheel arrangement (2'C1 ') (1'C2') ("Double Pacific"). With a diameter of 1,524 mm, its driving wheels were the largest of all South African articulated locomotives.
However, the cylinders of the GH were too small for this drive wheel diameter in connection with the high axle load of 18.4 t. The possible pulling power advantage of an articulated locomotive over a stiff-framed locomotive with the same axle load could therefore not be fully exploited.
The locomotives were equipped with a stoker . This was also the reason for choosing the Union Garratt design, as there is no relative movement between the coal box and the fire box. However, stokers were also used in normal Garratts and locomotives with a tender without any problems.
As with the Modified Fairlies and Class U, the large rear transition, compared to Garratts, resulted in increased pivot wear, which contributed to the class’s relatively early retirement. The two GH were decommissioned in 1957; most recently they were stationed at Glencoe in Natal . No copy has survived.
literature
- AE Durrant: Garratt locomotives of the world. Birkhäuser, Basel et al. 1984, ISBN 3-7643-1481-8 .
Individual evidence
- ↑ 2 C 1 - | - 1 C 2 Garrat Union locomotive. In: Die Lokomotive , year 1927, p. 217 (online at ANNO ).