South African Class GMA 4-8-2+2-8-4

Specifications
Specifications
Configuration:;
• Whyte	4-8-2+2-8-4 (Double Mountain)
• UIC	2'D1'+1'D2'h4t
Driver	3rd & 6th coupled axles
Gauge	3 ft 6 in (1,067 mm) Cape gauge
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)
Wheelbase	86 ft 4 in (26,314 mm)
• Axle spacing; (Asymmetrical)	1-2: 4 ft 10 in (1,473 mm) each; 2-3: 4 ft 9 in (1,448 mm) each; 3-4: 4 ft 10 in (1,473 mm) each
• Engine	30 ft 4 in (9,246 mm) each
• Leading	6 ft 10 in (2,083 mm) each
• Coupled	14 ft 5 in (4,394 mm) each
• Tender	35 ft 9 in (10,897 mm)
• Tender bogie	5 ft 9 in (1,753 mm)
Pivot centres	45 ft (13,716 mm)
Length:;
• Over couplers	93 ft 10 in (28,600 mm) engine; 43 ft 10+4⁄5 in (13,381 mm) tender; 137 ft 8+4⁄5 in (41,981 mm) total
Height	13 ft (3,962 mm)
Frame type	Cast
Axle load	♠ 15 LT 7 cwt (15,600 kg); ♥ 15 LT 14 cwt (15,950 kg)
• Leading	♠ 20 LT 16 cwt (21,130 kg) front; 20 LT 16 cwt (21,130 kg) rear; ♥ 21 LT 16 cwt (22,150 kg) front; 21 LT 9 cwt (21,790 kg) rear
• 1st coupled	♠ 14 LT 14 cwt (14,940 kg); ♥ 14 LT 18 cwt (15,140 kg)
• 2nd coupled	♠ 15 LT 5 cwt (15,490 kg); ♥ 15 LT 8 cwt (15,650 kg)
• 3rd coupled	♠ 15 LT 2 cwt (15,340 kg); ♥ 15 LT 6 cwt (15,550 kg)
• 4th coupled	♠ 14 LT 13 cwt (14,890 kg); ♥ 14 LT 17 cwt (15,090 kg)
• 5th coupled	♠ 14 LT 16 cwt (15,040 kg); ♥ 15 LT 4 cwt (15,440 kg)
• 6th coupled	♠ 15 LT 5 cwt (15,490 kg); ♥ 15 LT 12 cwt (15,850 kg)
• 7th coupled	♠ 15 LT 7 cwt (15,600 kg); ♥ 15 LT 14 cwt (15,950 kg)
• 8th coupled	♠ 14 LT 17 cwt (15,090 kg); ♥ 15 LT 4 cwt (15,440 kg)
• Trailing	♠ 12 LT 14 cwt (12,900 kg) front; 12 LT 17 cwt (13,060 kg) rear; ♥ 12 LT 17 cwt (13,060 kg) front; 13 LT 3 cwt (13,360 kg) rear
• Tender bogie	25 LT 4 cwt 2 qtr (25,630 kg)
• Tender axle	12 LT 12 cwt 1 qtr (12,810 kg)
Adhesive weight	♠ 119 LT 19 cwt (121,900 kg); ♥ 122 LT 3 cwt (124,100 kg)
Loco weight	♠ 187 LT 1 cwt (190,100 kg); ♥ 191 LT 8 cwt (194,500 kg)
Tender weight	50 LT 9 cwt 1 qtr (51,270 kg)
Total weight	♠ 237 LT 10 cwt 1 qtr (241,300 kg); ♥ 241 LT 17 cwt 1 qtr (245,700 kg)
Tender type	X-17 (2-axle bogies); X-20 (2-axle bogies); X-17, X-20 permitted
Fuel type	Coal
Fuel capacity	♠ 11 LT 12 cwt (11.8 t); ♥ 14 LT (14.2 t)
Water cap.	♠ 1,650 imp gal (7,500 L); ♥ 2,100 imp gal (9,500 L)
Tender cap.	6,790 imp gal (30,900 L)
Firebox:
• Type	Round-top
• Grate area	63.2 sq ft (5.87 m2)
Boiler:;
• Pitch	8 ft 6 in (2,591 mm)
• Diameter	6 ft 11+1⁄2 in (2,121 mm)
• Tube plates	13 ft 6+1⁄2 in (4,128 mm)
• Small tubes	282: 2 in (51 mm)
• Large tubes	50: 5+1⁄2 in (140 mm)
Boiler pressure	200 psi (1,379 kPa)
Safety valve	Ross-pop
Heating surface:
• Firebox	212 sq ft (19.7 m2)
• Tubes	2,974 sq ft (276.3 m2)
• Arch tubes	25.2 sq ft (2.34 m2)
• Total surface	3,211.2 sq ft (298.33 m2)
Superheater:;
• Heating area	747 sq ft (69.4 m2)
Cylinders	Four
Cylinder size	20+1⁄2 in (521 mm) bore; 26 in (660 mm) stroke
Valve gear	Walschaerts
Valve type	Piston
Loco brake	Vacuum brake
Train brakes	Vacuum brake
Couplers	AAR knuckle

Type and origin
Type and origin
	♠ Configured as Class GMA; ♥ Configured as Class GMAM
Power type	Steam
Designer	South African Railways; (L.C. Grubb)
Builder	Henschel and Son; Beyer, Peacock and Company; North British Locomotive Company
Serial number	Henschel 28680-28704, 29600-29629; BP 7550-7552, 7677-7681, 7750-7776, 7826-7855 ; NBL 27691-27702, 27769-27778, 27783-27792
Model	Class GMA
Build date	1953–1958
Total produced	120

South African Class GMA & GMAM 4-8-2+2-8-4
South African Class GMA & GMAM 4-8-2+2-8-4
	Class GMAM no. 4079 Lindie Lou, Capital Park, 30 September 2006
Power type
Type and origin
	♠ Configured as Class GMA; ♥ Configured as Class GMAM
Power type	Steam
Designer	South African Railways; (L.C. Grubb)
Builder	Henschel and Son; Beyer, Peacock and Company; North British Locomotive Company
Serial number	Henschel 28680-28704, 29600-29629; BP 7550-7552, 7677-7681, 7750-7776, 7826-7855 ; NBL 27691-27702, 27769-27778, 27783-27792
Model	Class GMA
Build date	1953–1958
Total produced	120
Configuration:;
Specifications
Configuration:;
• Whyte	4-8-2+2-8-4 (Double Mountain)
• UIC	2'D1'+1'D2'h4t
Driver	3rd & 6th coupled axles
Gauge	3 ft 6 in (1,067 mm) Cape gauge
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)
Wheelbase	86 ft 4 in (26,314 mm)
• Axle spacing; (Asymmetrical)	1-2: 4 ft 10 in (1,473 mm) each; 2-3: 4 ft 9 in (1,448 mm) each; 3-4: 4 ft 10 in (1,473 mm) each
• Engine	30 ft 4 in (9,246 mm) each
• Leading	6 ft 10 in (2,083 mm) each
• Coupled	14 ft 5 in (4,394 mm) each
• Tender	35 ft 9 in (10,897 mm)
• Tender bogie	5 ft 9 in (1,753 mm)
Pivot centres	45 ft (13,716 mm)
Length:;
• Over couplers	93 ft 10 in (28,600 mm) engine; 43 ft 10+4⁄5 in (13,381 mm) tender; 137 ft 8+4⁄5 in (41,981 mm) total
Height	13 ft (3,962 mm)
Frame type	Cast
Axle load	♠ 15 LT 7 cwt (15,600 kg); ♥ 15 LT 14 cwt (15,950 kg)
• Leading	♠ 20 LT 16 cwt (21,130 kg) front; 20 LT 16 cwt (21,130 kg) rear; ♥ 21 LT 16 cwt (22,150 kg) front; 21 LT 9 cwt (21,790 kg) rear
• 1st coupled	♠ 14 LT 14 cwt (14,940 kg); ♥ 14 LT 18 cwt (15,140 kg)
• 2nd coupled	♠ 15 LT 5 cwt (15,490 kg); ♥ 15 LT 8 cwt (15,650 kg)
• 3rd coupled	♠ 15 LT 2 cwt (15,340 kg); ♥ 15 LT 6 cwt (15,550 kg)
• 4th coupled	♠ 14 LT 13 cwt (14,890 kg); ♥ 14 LT 17 cwt (15,090 kg)
• 5th coupled	♠ 14 LT 16 cwt (15,040 kg); ♥ 15 LT 4 cwt (15,440 kg)
• 6th coupled	♠ 15 LT 5 cwt (15,490 kg); ♥ 15 LT 12 cwt (15,850 kg)
• 7th coupled	♠ 15 LT 7 cwt (15,600 kg); ♥ 15 LT 14 cwt (15,950 kg)
• 8th coupled	♠ 14 LT 17 cwt (15,090 kg); ♥ 15 LT 4 cwt (15,440 kg)
• Trailing	♠ 12 LT 14 cwt (12,900 kg) front; 12 LT 17 cwt (13,060 kg) rear; ♥ 12 LT 17 cwt (13,060 kg) front; 13 LT 3 cwt (13,360 kg) rear
• Tender bogie	25 LT 4 cwt 2 qtr (25,630 kg)
• Tender axle	12 LT 12 cwt 1 qtr (12,810 kg)
Adhesive weight	♠ 119 LT 19 cwt (121,900 kg); ♥ 122 LT 3 cwt (124,100 kg)
Loco weight	♠ 187 LT 1 cwt (190,100 kg); ♥ 191 LT 8 cwt (194,500 kg)
Tender weight	50 LT 9 cwt 1 qtr (51,270 kg)
Total weight	♠ 237 LT 10 cwt 1 qtr (241,300 kg); ♥ 241 LT 17 cwt 1 qtr (245,700 kg)
Tender type	X-17 (2-axle bogies); X-20 (2-axle bogies); X-17, X-20 permitted
Fuel type	Coal
Fuel capacity	♠ 11 LT 12 cwt (11.8 t); ♥ 14 LT (14.2 t)
Water cap.	♠ 1,650 imp gal (7,500 L); ♥ 2,100 imp gal (9,500 L)
Tender cap.	6,790 imp gal (30,900 L)
Firebox:
• Type	Round-top
• Grate area	63.2 sq ft (5.87 m2)
Boiler:;
• Pitch	8 ft 6 in (2,591 mm)
• Diameter	6 ft 11+1⁄2 in (2,121 mm)
• Tube plates	13 ft 6+1⁄2 in (4,128 mm)
• Small tubes	282: 2 in (51 mm)
• Large tubes	50: 5+1⁄2 in (140 mm)
Boiler pressure	200 psi (1,379 kPa)
Safety valve	Ross-pop
Heating surface:
• Firebox	212 sq ft (19.7 m2)
• Tubes	2,974 sq ft (276.3 m2)
• Arch tubes	25.2 sq ft (2.34 m2)
• Total surface	3,211.2 sq ft (298.33 m2)
Superheater:;
• Heating area	747 sq ft (69.4 m2)
Cylinders	Four
Cylinder size	20+1⁄2 in (521 mm) bore; 26 in (660 mm) stroke
Valve gear	Walschaerts
Valve type	Piston
Loco brake	Vacuum brake
Train brakes	Vacuum brake
Couplers	AAR knuckle
Tractive effort
Performance figures
Tractive effort	60,700 lbf (270 kN) @ 75%
Operators
Career
Operators	South African Railways
Class	Class GMA & GMAM
Number in class	120
Numbers	4051–4170
Delivered	1954–1958
First run	1954
Withdrawn	1988
Disposition	11 preserved, remainder scrapped

The South African Railways Class GMA 4-8-2+2-8-4 of 1954 is an articulated steam locomotive.

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.