South African Class GMA 4-8-2+2-8-4 The South African Railways Class GMA 4-8-2+2-8-4 of 1954 South African Class GMA & GMAM was an articulated steam locomotive. 4-8-2+2-8-4 Between 1954 and 1958, the South African Railways placed 120 Class GMA Garratt articulated steam locomotives with a 4-8-2+2- 8-4 Double Mountain type wheel arrangement in service. All the locomotives could be configured as either a Class GMA branch line or a Class GMAM mainline engine. This was the most numerous Garratt class in the world.[1][2][3][4][5] Contents Manufacturers Characteristics Class GMAM no. 4079 Lindie Lou, Capital Park, 30 September 2006 Service South African Railways Type and origin Zimbabwe and Mozambique ♠ Configured as Class GMA Industrial, private ownership and preservation ♥ Configured as Class GMAM Preservation Power type Steam Works numbers Designer Illustration South African Railways References (L.C. Grubb) External links Builder Henschel and Son Manufacturers Beyer, Peacock and Company The light rail branch line Class GMA and mainline Class GMAM North British Garratt locomotive, a single Class which could be configured for Locomotive either branch line or mainline working, was a development of the Company large Class GM branch line locomotive which was introduced on Serial number Henschel 28680- the South African Railways (SAR) in 1938. Like the Class GM, 28704, 29600- the Class GMA was a tank-and-tender Garratt which ran with a 29629 semi-permanently coupled auxiliary water tender to augment its BP 7550-7552, meagre water capacity.[1][3][6] 7677-7681, 7750- The locomotive was designed in 1952 under the supervision of 7776, 7826-7855 L.C. Grubb, Chief Mechanical Engineer (CME) of the SAR from NBL 27691- 1949 to 1954. An order for the first 25 of these locomotives was 27702, 27769- placed with Henschel and Son in Germany. They were built in 27778, 27783- 1953 and were delivered and placed in service in 1954, numbered 27792 in the range from 4051 to 4075. These first 25 locomotives were Model Class GMA equipped with Type X-17 water Build date 1953-1958 tenders, built by the SAR in its Total produced 120 Pietermaritzburg shops in Specifications 1953.[7][8][9][10] Configuration: A second batch of 35 • Whyte 4-8-2+2-8-4 locomotives was delivered by (Double Beyer, Peacock and Company Mountain) (BP) in 1956. Of these, 23 were built by BP and numbered in • UIC 2'D1'+1'D2'h4t the range from 4076 to 4098, Driver 3rd & 6th L.C. Grubb while the other twelve, coupled axles numbered in the range from Gauge 3 ft 6 in 4099 to 4110, had been subcontracted by BP to the North British (1,067 mm) Locomotive Company (NBL). These twelve engines therefore bore Cape gauge works plates showing BP as well as NBL as builders.[7][11][12][13] Leading dia. 30 in (762 mm) Coupled dia. 54 in (1,372 mm) Trailing dia. 30 in (762 mm) Tender wheels 34 in (864 mm) Minimum curve 275 ft (84 m) BP & NBL works plate off no. 4140 Wheelbase 86 ft 4 in (26,314 mm) This was followed by a third and final batch of sixty locomotives • Engine 30 ft 4 in in 1958. Of these, thirty were delivered by BP, of which only ten, (9,246 mm) numbered in the range from 4121 to 4130, had actually been built each by BP. The other twenty, numbered in the ranges from 4111 to • Leading 6 ft 10 in 4120 and 4131 to 4140, had once again been subcontracted by BP (2,083 mm) to NBL. These twenty therefore also bore works plates showing each BP as well as NBL as builders. Number 4140 turned out to be the • Coupled 14 ft 5 in last steam locomotive built by North British. The other thirty (4,394 mm) locomotives of the third batch, numbered in the range from 4141 to each 4170, were again built by Henschel in Germany.[1][7][8][11][12][13] • Tender 35 ft 9 in The locomotives of the second and third batches were equipped (10,897 mm) with Type X-20 water tenders, built in the Pietermaritzburg shops • Tender bogie 5 ft 9 in between 1956 and 1958.[1][9][14] (1,753 mm) Pivot centres 45 ft Characteristics (13,716 mm) Wheel spacing The light rail branch line Class GMA and the mainline Class 1-2: 4 ft 10 in (Asymmetrical) GMAM were the same locomotive of which the water and coal (1,473 mm) capacities could be adjusted to suit by installing or removing plates each in the coal and water spaces. As a result, it is virtually impossible 2-3: 4 ft 9 in to list the GMA and GMAM versions separately since they could (1,448 mm) easily be converted back and forth between the two versions and each often were. Up until about 1962, for example, the division was 20 3-4: 4 ft 10 in Class GMA and 100 Class GMAM, but by 1969 there were 69 (1,473 mm) Class GMA and 39 Class GMAM, two locomotives having by then each been scrapped after accident damage. By 1975, on the other hand, Length: there were only 25 Class GMA against 93 Class GMAM.[1][3][4] • Over couplers 93 ft 10 in The locomotive was thoroughly modern in design, with a one- (28,600 mm) piece cast steel frame with Franklin spring-loaded wedge horns, engine 4 manufactured by Commonwealth Steel Castings Corporation in the 43 ft 10 ⁄5 in United States of America. Like the Class 25 locomotive, it had (13,381 mm) roller bearing axle boxes on all wheels, but not on the crank-pins, tender 4 with cannon boxes on all axles, except those of the inner Bissel 137 ft 8 ⁄5 in trucks which had outside bearings. It had mechanical lubrication (41,981 mm) throughout, self-adjusting pivots, a U-shaped foundation ring total welded to the inner and outer firebox bottom edges, and an all- Height 13 ft (3,962 mm) welded firebox. The engine units also had Commonwealth cast Frame type Cast steel type frames.[1][3][4][5][15] Axle load ♠ 15 LT 7 cwt 1 The boiler's inside diameter was 6 feet 11 ⁄2 inches (2,121 (15,600 kg) 1 millimetres) at the first ring and 7 feet 1 ⁄4 inches (2,165 ♥ 15 LT 14 cwt millimetres) at the firebox end. The boiler had an inspection (15,950 kg) manhole, fitted to the top of the boiler aft of the dome. The • Leading ♠ 20 LT 16 cwt locomotive was superheated, with a mechanical stoker and (21,130 kg) front Walschaerts valve gear. It could negotiate curves of 275 feet (84 20 LT 16 cwt 3 metres) radius with a gauge widening of not more than ⁄4 inch (19 (21,130 kg) rear 1 millimetres) and a superelevation of 4 ⁄2 inches (114 ♥ 21 LT 16 cwt millimetres).[1][3] (22,150 kg) front 21 LT 9 cwt Some of these locomotives, intended for working in areas where (21,790 kg) rear there were tunnels such as on the East London mainline, were initially equipped with steam-operated smoke deflecting cowls • 1st coupled ♠ 14 LT 14 cwt over their chimneys. When the smoke cowls were later removed, (14,940 kg) these specific locomotives could still be identified by their almost ♥ 14 LT 18 cwt non-existent chimneys which had to be shorter in order to enable (15,140 kg) the cowls to fit within the loading gauge.[1][5] • 2nd coupled ♠ 15 LT 5 cwt (15,490 kg) As was done with the predecessor Class GM, the new locomotive ♥ 15 LT 8 cwt carried water only in its front tank, but with the capacity increased (15,650 kg) from the Class GM's 1,600 imperial gallons (7,270 litres) to either • 3rd coupled ♠ 15 LT 2 cwt 1,650 imperial gallons (7,500 litres) for the Class GMA or 2,100 (15,340 kg) imperial gallons (9,550 litres) for the Class GMAM. Likewise, the ♥ 15 LT 6 cwt rear bunker carried only coal, but with the capacity increased from (15,550 kg) the Class GM's 10 long tons (10,160 kilograms) to either 11 long tons 12 hundredweight (11,790 kilograms) for the Class GMA or • 4th coupled ♠ 14 LT 13 cwt 14 long tons (14,220 kilograms) for the Class GMAM.[1][4] (14,890 kg) ♥ 14 LT 17 cwt As with the Class GM, the Class GMA's water supply was (15,090 kg) augmented by semi-permanently coupling a purpose-built auxiliary • 5th coupled ♠ 14 LT 16 cwt water tender. The first batch of 25 locomotives were tended by the (15,040 kg) same Type X-17 ♥ 15 LT 4 cwt water tender (15,440 kg) which was used • 6th coupled ♠ 15 LT 5 cwt with the Class (15,490 kg) GM, with a ♥ 15 LT 12 cwt capacity of (15,850 kg) between 6,750 • 7th coupled ♠ 15 LT 7 cwt and 6,815 (15,600 kg) imperial gallons Type X-17 water tender ♥ 15 LT 14 cwt (30,700 and (15,950 kg) 31,000 litres). The • 8th coupled rest of the ♠ 14 LT 17 cwt locomotives were (15,090 kg) tended by Type ♥ 15 LT 4 cwt X-20 water (15,440 kg) tenders with a • Trailing ♠ 12 LT 14 cwt capacity of 6,790 (12,900 kg) front imperial gallons 12 LT 17 cwt (30,900 litres).