South African Class 12A 4-8-2

Specifications
Specifications
Configuration:;
• Whyte	4-8-2 (Mountain)
• UIC	2'D1'h2
Driver	2nd coupled axle
Gauge	3 ft 6 in (1,067 mm) Cape gauge
Leading dia.	28+1⁄2 in (724 mm)
Coupled dia.	51 in (1,295 mm)
Trailing dia.	33 in (838 mm)
Tender wheels	34 in (864 mm)
Wheelbase	♣ 58 ft 7+1⁄4 in (17,863 mm); ♦ 61 ft 7+3⁄8 in (18,780 mm)
• Engine	32 ft 1 in (9,779 mm)
• Leading	6 ft 2 in (1,880 mm)
• Coupled	13 ft 6 in (4,115 mm)
• Tender	♣ 16 ft 9 in (5,105 mm); ♦ 20 ft 5 in (6,223 mm)
• Tender bogie	♣ 4 ft 7 in (1,397 mm); ♦ 6 ft 2 in (1,880 mm)
Length:;
• Over couplers	♣ 66 ft 11+5⁄8 in (20,412 mm); ♦ 69 ft 7 in (21,209 mm)
Height	♠ 12 ft 10 in (3,912 mm); ♥ 13 ft (3,962 mm)
Frame type	Plate
Axle load	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 8 cwt (17,680 kg)
• Leading	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 14 cwt (17,980 kg)
• 1st coupled	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT (17,270 kg)
• 2nd coupled	♠ 17 LT 5 cwt (17,530 kg); ♥ 17 LT 4 cwt (17,480 kg)
• 3rd coupled	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 8 cwt (17,680 kg)
• 4th coupled	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 7 cwt (17,630 kg)
• Trailing	♠♥ 12 LT 12 cwt (12,800 kg)
• Tender bogie	Bogie 1:; ♣ 27 LT 10 cwt (27,940 kg); ♦ 32 LT 18 cwt (33,430 kg); Bogie 2:; ♣ 23 LT 11 cwt (23,930 kg); ♦ 33 LT 2 cwt (33,630 kg)
• Tender axle	♣ 13 LT 15 cwt (13,970 kg); ♦ 16 LT 11 cwt (16,820 kg)
Adhesive weight	♠ 69 LT 3 cwt (70,260 kg); ♥ 68 LT 19 cwt (70,060 kg)
Loco weight	♠ 99 LT 1 cwt (100,600 kg); ♥ 99 LT 5 cwt (100,800 kg)
Tender weight	♣ 51 LT 1 cwt (51,870 kg); ♦ 66 LT (67,060 kg)
Total weight	♠♣ 150 LT 2 cwt (152,500 kg); ♥♣ 150 LT 6 cwt (152,700 kg); ♠♦ 165 LT 1 cwt (167,700 kg); ♥♦ 165 LT 5 cwt (167,900 kg)
Tender type	♣ MP1 (2-axle bogies); ♦ MT (2-axle bogies); MP, MP1, MR, MS, MT, MT1, MT2, MX, MY, MY1 permitted
Fuel type	Coal
Fuel capacity	♣ 10 LT (10.2 t); ♦ 12 LT (12.2 t)
Water cap.	♣ 4,250 imp gal (19,300 L); ♦ 6,000 imp gal (27,300 L)
Firebox:
• Type	♠ Belpaire – ♥ Round-top
• Grate area	♠ 40.5 sq ft (3.76 m2); ♥ 41 sq ft (3.8 m2)
Boiler:;
• Pitch	♠ 7 ft 9 in (2,362 mm); ♥ 8 ft 6 in (2,591 mm)
• Diameter	♠ 5 ft 10+1⁄2 in (1,791 mm); ♥ 6 ft (1,829 mm)
• Tube plates	♠ 18 ft (5,486 mm); ♥ 19 ft 4 in (5,893 mm)
• Small tubes	♠ 159: 2+1⁄4 in (57 mm); ♥ 119: 2+1⁄2 in (64 mm)
• Large tubes	♠ 24 5+1⁄2 in (140 mm); ♥ 30: 5+1⁄2 in (140 mm)
Boiler pressure	♠♥ 190 psi (1,310 kPa)
Safety valve	♠ Ramsbottom – ♥ Ross Pop
Heating surface:
• Firebox	♠ 209 sq ft (19.4 m2); ♥ 164 sq ft (15.2 m2)
• Tubes	♠ 2,301 sq ft (213.8 m2); ♥ 2,338 sq ft (217.2 m2)
• Total surface	♠ 2,510 sq ft (233 m2); ♥ 2,502 sq ft (232.4 m2)
Superheater:;
• Heating area	♠ 466 sq ft (43.3 m2); ♥ 480 sq ft (45 m2)
Cylinders	Two
Cylinder size	24 in (610 mm) bore; 26 in (660 mm) stroke
Valve gear	Walschaerts
Valve type	Piston
Couplers	Johnston link-and-pin; AAR knuckle (1930s)

Type and origin
Type and origin
	♠ Class 12A as built with a Belpaire firebox; ♥ Class 12AR rebuilt with a round-topped firebox; ♣ Type MP1 tender – ♦ Type MT tender
Power type	Steam
Designer	South African Railways; (D.A. Hendrie)
Builder	North British Locomotive Company; Henschel and Son
Serial number	NBL 21738-21757, 22751-22765, 23891-23903; Henschel 21046-21051, 21428-21440
Model	Class 12A
Build date	1919–1929
Total produced	75

South African Class 12A & 12AR 4-8-2
South African Class 12A & 12AR 4-8-2
	Class 12AR no. 1535 at Maraisburg, 27 April 2009
Power type
Type and origin
	♠ Class 12A as built with a Belpaire firebox; ♥ Class 12AR rebuilt with a round-topped firebox; ♣ Type MP1 tender – ♦ Type MT tender
Power type	Steam
Designer	South African Railways; (D.A. Hendrie)
Builder	North British Locomotive Company; Henschel and Son
Serial number	NBL 21738-21757, 22751-22765, 23891-23903; Henschel 21046-21051, 21428-21440
Model	Class 12A
Build date	1919–1929
Total produced	75
Configuration:;
Specifications
Configuration:;
• Whyte	4-8-2 (Mountain)
• UIC	2'D1'h2
Driver	2nd coupled axle
Gauge	3 ft 6 in (1,067 mm) Cape gauge
Leading dia.	28+1⁄2 in (724 mm)
Coupled dia.	51 in (1,295 mm)
Trailing dia.	33 in (838 mm)
Tender wheels	34 in (864 mm)
Wheelbase	♣ 58 ft 7+1⁄4 in (17,863 mm); ♦ 61 ft 7+3⁄8 in (18,780 mm)
• Engine	32 ft 1 in (9,779 mm)
• Leading	6 ft 2 in (1,880 mm)
• Coupled	13 ft 6 in (4,115 mm)
• Tender	♣ 16 ft 9 in (5,105 mm); ♦ 20 ft 5 in (6,223 mm)
• Tender bogie	♣ 4 ft 7 in (1,397 mm); ♦ 6 ft 2 in (1,880 mm)
Length:;
• Over couplers	♣ 66 ft 11+5⁄8 in (20,412 mm); ♦ 69 ft 7 in (21,209 mm)
Height	♠ 12 ft 10 in (3,912 mm); ♥ 13 ft (3,962 mm)
Frame type	Plate
Axle load	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 8 cwt (17,680 kg)
• Leading	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 14 cwt (17,980 kg)
• 1st coupled	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT (17,270 kg)
• 2nd coupled	♠ 17 LT 5 cwt (17,530 kg); ♥ 17 LT 4 cwt (17,480 kg)
• 3rd coupled	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 8 cwt (17,680 kg)
• 4th coupled	♠ 17 LT 6 cwt (17,580 kg); ♥ 17 LT 7 cwt (17,630 kg)
• Trailing	♠♥ 12 LT 12 cwt (12,800 kg)
• Tender bogie	Bogie 1:; ♣ 27 LT 10 cwt (27,940 kg); ♦ 32 LT 18 cwt (33,430 kg); Bogie 2:; ♣ 23 LT 11 cwt (23,930 kg); ♦ 33 LT 2 cwt (33,630 kg)
• Tender axle	♣ 13 LT 15 cwt (13,970 kg); ♦ 16 LT 11 cwt (16,820 kg)
Adhesive weight	♠ 69 LT 3 cwt (70,260 kg); ♥ 68 LT 19 cwt (70,060 kg)
Loco weight	♠ 99 LT 1 cwt (100,600 kg); ♥ 99 LT 5 cwt (100,800 kg)
Tender weight	♣ 51 LT 1 cwt (51,870 kg); ♦ 66 LT (67,060 kg)
Total weight	♠♣ 150 LT 2 cwt (152,500 kg); ♥♣ 150 LT 6 cwt (152,700 kg); ♠♦ 165 LT 1 cwt (167,700 kg); ♥♦ 165 LT 5 cwt (167,900 kg)
Tender type	♣ MP1 (2-axle bogies); ♦ MT (2-axle bogies); MP, MP1, MR, MS, MT, MT1, MT2, MX, MY, MY1 permitted
Fuel type	Coal
Fuel capacity	♣ 10 LT (10.2 t); ♦ 12 LT (12.2 t)
Water cap.	♣ 4,250 imp gal (19,300 L); ♦ 6,000 imp gal (27,300 L)
Firebox:
• Type	♠ Belpaire – ♥ Round-top
• Grate area	♠ 40.5 sq ft (3.76 m2); ♥ 41 sq ft (3.8 m2)
Boiler:;
• Pitch	♠ 7 ft 9 in (2,362 mm); ♥ 8 ft 6 in (2,591 mm)
• Diameter	♠ 5 ft 10+1⁄2 in (1,791 mm); ♥ 6 ft (1,829 mm)
• Tube plates	♠ 18 ft (5,486 mm); ♥ 19 ft 4 in (5,893 mm)
• Small tubes	♠ 159: 2+1⁄4 in (57 mm); ♥ 119: 2+1⁄2 in (64 mm)
• Large tubes	♠ 24 5+1⁄2 in (140 mm); ♥ 30: 5+1⁄2 in (140 mm)
Boiler pressure	♠♥ 190 psi (1,310 kPa)
Safety valve	♠ Ramsbottom – ♥ Ross Pop
Heating surface:
• Firebox	♠ 209 sq ft (19.4 m2); ♥ 164 sq ft (15.2 m2)
• Tubes	♠ 2,301 sq ft (213.8 m2); ♥ 2,338 sq ft (217.2 m2)
• Total surface	♠ 2,510 sq ft (233 m2); ♥ 2,502 sq ft (232.4 m2)
Superheater:;
• Heating area	♠ 466 sq ft (43.3 m2); ♥ 480 sq ft (45 m2)
Cylinders	Two
Cylinder size	24 in (610 mm) bore; 26 in (660 mm) stroke
Valve gear	Walschaerts
Valve type	Piston
Couplers	Johnston link-and-pin; AAR knuckle (1930s)
Tractive effort
Performance figures
Tractive effort	♠♥ 41,840 lbf (186.1 kN) @ 75%
Operators
Career
Operators	South African Railways
Class	Class 12A & 12AR
Number in class	SAR 67, Industrial 8
Numbers	1520–1550, 2103–2138
Delivered	1919–1929
First run	1919
Withdrawn	1980s
	The leading coupled axle had flangeless wheels

The South African Railways Class 12A 4-8-2 of 1919 was a steam locomotive.

Between 1919 and 1929, the South African Railways placed 67 Class 12A steam locomotives with a 4-8-2 Mountain type wheel arrangement in service. Between 1947 and 1953, eight were also built for industrial use.^[1]^[2]^[3]

^ Espitalier, T.J.; Day, W.A.J. (1945). The Locomotive in South Africa – A Brief History of Railway Development. Chapter VII – South African Railways (Continued). South African Railways and Harbours Magazine, October 1945. pp. 779-783.
^ Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 55. ISBN 0869772112.
^ Durrant, AE (1989). Twilight of South African Steam (1st ed.). Newton Abbott: David & Charles. pp. 60–62. ISBN 0715386387.

[SAR&H_Oct_1945-1] Espitalier, T.J.; Day, W.A.J. (1945). The Locomotive in South Africa – A Brief History of Railway Development. Chapter VII – South African Railways (Continued). South African Railways and Harbours Magazine, October 1945. pp. 779-783.

[Paxton-Bourne-2] Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 55. ISBN 0869772112.

[Durrant-3] Durrant, AE (1989). Twilight of South African Steam (1st ed.). Newton Abbott: David & Charles. pp. 60–62. ISBN 0715386387.

[1]

[2]

[3]

South African Class 12A 4-8-2

From Wikipedia, the free encyclopedia · View on Wikipedia