South African Class GD 2-6-2+2-6-2

South African Class GD 2-6-2+2-6-2
Class GD Garratt, c. 1965
Type and origin Power type Steam Designer Beyer, Peacock and Company Builder Beyer, Peacock and Company Serial number 6263-6266, 6281-6290 Model Class GD Build date 1925-1926 Total produced 14
Specifications Configuration: ​  • Whyte 2-6-2+2-6-2 (Double Prairie)  • UIC 1'C1'+1'C1'h4 Driver 3rd & 4th coupled axles Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia. 28 1⁄2 in (724 mm) Coupled dia. 46 in (1,168 mm) Trailing dia. 28 1⁄2 in (724 mm) Wheelbase 58 ft 4 in (17,780 mm)  • Engine 18 ft 9 in (5,715 mm) each  • Coupled 8 ft 6 in (2,591 mm) each Pivot centres 30 ft 6 in (9,296 mm) Length: ​  • Over couplers 65 ft 3⁄4 in (19,831 mm) Height 12 ft 10 1⁄4 in (3,918 mm) Frame type Plate Axle load 12 LT 15 cwt (12,950 kg)  • Leading 11 LT 7 cwt (11,530 kg) front 11 LT 16 cwt (11,990 kg) rear  • 1st coupled 12 LT 10 cwt (12,700 kg)  • 2nd coupled 12 LT 10 cwt (12,700 kg)  • 3rd coupled 12 LT 10 cwt (12,700 kg)  • 4th coupled 12 LT 11 cwt (12,750 kg)  • 5th coupled 12 LT 11 cwt (12,750 kg)  • 6th coupled 12 LT 15 cwt (12,950 kg)  • Trailing 7 LT 15 cwt (7,874 kg) front 7 LT 16 cwt (7,925 kg) rear Adhesive weight 75 LT 7 cwt (76,560 kg) Loco weight 114 LT 1 cwt (115,900 kg) Fuel type Coal Fuel capacity 5 LT (5.1 t) as built 9 LT (9.1 t) no. 2220 Water cap 2,300 imp gal (10,500 l) front 1,500 imp gal (6,820 l) rear Firebox type Belpaire  • Firegrate area 40 sq ft (3.7 m2) Boiler: ​  • Pitch 7 ft 9 1⁄4 in (2,369 mm)  • Diameter 6 ft (1,829 mm)  • Tube plates 10 ft 7 7⁄8 in (3,248 mm)  • Small tubes 184: 2 in (51 mm)  • Large tubes 32: 5 1⁄2 in (140 mm) Boiler pressure 180 psi (1,241 kPa) Safety valve Ramsbottom Heating surface 1,689 sq ft (156.9 m2)  • Tubes 1,517 sq ft (140.9 m2)  • Firebox 172 sq ft (16.0 m2) Superheater: ​  • Heating area 370 sq ft (34 m2) Cylinders Four Cylinder size 15 in (381 mm) bore 24 in (610 mm) stroke Valve gear Walschaerts Valve type Piston Couplers Bell link-and-pin AAR knuckle (1940s-1950s)
Performance figures Tractive effort 31,690 lbf (141.0 kN) @ 75%
Career Operators South African Railways Class Class GD Number in class 14 Numbers 2220-2223, 2228-2237 Delivered 1925-1926 First run 1925 Withdrawn 1967

The South African Railways Class GD 2-6-2+2-6-2 of 1925 was an articulated steam locomotive.

In 1925, the South African Railways placed four Class GD Garratt articulated locomotives with a 2-6-2+2-6-2 Double Prairie type wheel arrangement in branchline service. Another ten of these locomotives were delivered in 1926.

The Class GD 2-6-2+2-6-2 Double Prairie type Garratt locomotive was marginally larger and more powerful than its predecessor Class GC, with a heavier axle loading, but also intended for branchline work. Four locomotives were delivered by Beyer, Peacock and Company in December 1925, numbered in the range from 2220 to 2223. These were followed in January 1926 by ten more from the same manufacturer, seven of them built in 1925 and numbered in the range from 2228 to 2234, and the last three built in 1926 and numbered in the range from 2235 to 2237.

They locomotives were superheated and had plate frames, Belpaire fireboxes, piston valves and Walschaerts valve gear.

As built, their coal bunkers had a 5 long tons (5.1 tonnes) capacity. At some stage, the coal bunker of no. 2220 was enlarged to a 9 long tons (9.1 tonnes) capacity.

The locomotives were placed in service on the North Coast and the Pietermaritzburg to Franklin lines in Natal. From 1926, some were allocated to Paardeneiland to work on the line from Cape Town across Sir Lowry's Pass to Caledon in the Overberg. They were the first Garratts to work the Caledon line and were later joined by the two Class GK Garratts after the New Cape Central Railway was absorbed by the SAR in 1925.

The Class GD proved themselves as handy and trouble-free locomotives and gave good service for more than forty years. They were later allocated to the Cape Midland system to work across the Montagu Pass between George and Oudtshoorn for many years until they were finally all allocated to the Port Alfred branch. They remained there until they were withdrawn from service in 1967.