South African Class 12B 4-8-2

South African Class 12B & 12R 4-8-2

Class 12R no. 1931 at Port Elizabeth sheds, with Belpaire firebox, c. 1930

Type and origin
♠ Class 12B as built with a Belpaire firebox ♥ Class 12R rebuilt with a Watson Standard boiler
Power type	Steam
Designer	South African Railways (D.A. Hendrie)
Builder	Baldwin Locomotive Works
Serial number	52476, 52558-52559, 52583-52584, 52649-52651, 52690-52693, 52712-52713, 52723-52724, 52754-52767
Model	Class 12B
Build date	1920
Total produced	30

Specifications
Configuration:
• Whyte	4-8-2 (Mountain)
• UIC	♠ 2′D1’n2 - ♥ 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 3+3⁄4 in (17,774 mm)
• Engine	31 ft 9+1⁄2 in (9,690 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)
• Tender bogie	4 ft 7 in (1,397 mm)
Length:
• Over couplers	66 ft 8 in (20,320 mm)
Height	♠ 12 ft 10 in (3,912 mm) ♥ 12 ft 7+1⁄2 in (3,848 mm)
Frame type	Plate
Axle load	♠ 16 LT 15 cwt (17,020 kg) ♥ 17 LT 9 cwt (17,730 kg)
• Leading	♠ 15 LT 13 cwt (15,900 kg) ♥ 16 LT 2 cwt (16,360 kg)
• 1st coupled	♠ 16 LT 13 cwt (16,920 kg) ♥ 16 LT 15 cwt (17,020 kg)
• 2nd coupled	♠ 16 LT 15 cwt (17,020 kg) ♥ 17 LT 9 cwt (17,730 kg)
• 3rd coupled	♠ 16 LT 14 cwt (16,970 kg) ♥ 16 LT 17 cwt (17,120 kg)
• 4th coupled	♠ 16 LT 15 cwt (17,020 kg) ♥ 16 LT 15 cwt (17,020 kg)
• Trailing	♠ 12 LT 4 cwt (12,400 kg) ♥ 11 LT 16 cwt (11,990 kg)
• Tender bogie	Bogie 1: 27 LT 10 cwt (27,940 kg) Bogie 2: 23 LT 11 cwt (23,930 kg)
• Tender axle	13 LT 15 cwt (13,970 kg)
Adhesive weight	♠ 66 LT 17 cwt (67,920 kg) ♥ 67 LT 16 cwt (68,890 kg)
Loco weight	♠ 94 LT 14 cwt (96,220 kg) ♥ 95 LT 14 cwt (97,240 kg)
Tender weight	51 LT 1 cwt (51,870 kg)
Total weight	♠ 145 LT 15 cwt (148,100 kg) ♥ 146 LT 15 cwt (149,100 kg)
Tender type	MP1 (2-axle bogies) MP, MP1, MR, MS, MT, MT1, MT2, MX, MY, MY1 permitted
Fuel type	Coal
Fuel capacity	10 LT (10,160 kg)
Water cap.	4,250 imp gal (19,300 L)
Firebox type	♠ Belpaire - ♥ Round-top
• Firegrate area	♠ 40 sq ft (3.7 m²) ♥ 37 sq ft (3.4 m²)
Boiler:
• Model	Watson Standard no. 2
• Pitch	♠ 7 ft 7 in (2,311 mm) ♥ 7 ft 8+1⁄4 in (2,343 mm)
• Diameter	♠♥ 5 ft 7+1⁄2 in (1,714 mm)
• Tube plates	♠ 20 ft (6,096 mm) ♥ 19 ft 4 in (5,893 mm) steel ♥ 19 ft 3+5⁄8 in (5,883 mm)
• Small tubes	♠ 139: 2+1⁄4 in (57 mm) ♥ 87: 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 - ♥ Pop
Heating surface	♠ 2,488 sq ft (231.1 m²) ♥ 2,075 sq ft (192.8 m²)
• Tubes	♠ 2,328 sq ft (216.3 m²) ♥ 1,933 sq ft (179.6 m²)
• Firebox	♠ 160 sq ft (15 m²) ♥ 142 sq ft (13.2 m²)
Superheater:
• Heating area	♠ 574 sq ft (53.3 m²) ♥ 492 sq ft (45.7 m²)
Cylinders	Two
Cylinder size	22+1⁄2 in (572 mm) bore 26 in (660 mm) stroke
Valve gear	Walschaerts
Valve type	Piston
Couplers	Johnston link-and-pin AAR knuckle (1930s)

Performance figures
Tractive effort	♠♥ 36,780 lbf (163.6 kN) @ 75%

Career
Operators	South African Railways
Class	Class 12B & 12R
Number in class	30
Numbers	1931-1960
Delivered	1920
First run	1920
Withdrawn	c. 1984

The leading coupled axle had flangeless wheels

The South African Railways Class 12B 4-8-2 of 1920 was a steam locomotive.

In 1920, the South African Railways placed thirty Class 12B steam locomotives with a 4-8-2 Mountain type wheel arrangement in service.^[1]^[2]

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Transcription

Manufacturer

In May 1920, an additional thirty locomotives, built to the Class 12 design of SAR Chief Mechanical Engineer (CME) D.A. Hendrie, were delivered to the South African Railways (SAR) from Baldwin Locomotive Works in the United States of America. Most of them were erected in the SAR workshops, but a few were contracted to James Brown and Company at Durban for erection. Even though they were very similar to the second and subsequent orders of the Class 12 which was also designed specifically for the Midland System, they were classified separately as Class 12B and numbered in the range from 1931 to 1960. Like the Class 12, they were also built with plate frames, Walschaerts valve gear and Belpaire fireboxes.^[1]^[2]^[3]^[4]

Classification

The separate 12B classification has been ascribed to the fact that the wheelbase of the leading bogie was 2 inches (51 millimetres) longer than on the original Class 12 locomotives. This was probably not the reason, bearing in mind that only the first eight out of altogether 46 Class 12 locomotives were built with leading bogies with a 6 feet (1,829 millimetres) wheelbase, while the other thirty-eight all had leading bogies with a 6 feet 2 inches (1,880 millimetres) wheelbase, the same as the Class 12B. More likely, the separate classification was simply based on the fact that the Class 12 was British-built while the Class 12B was American-built.^[1]^[2]^[3]

Watson Standard boilers

During the 1930s, many serving locomotives were reboilered with a standard boiler type designed by then CME A.G. Watson as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.^[2]^[5]^[6]

All thirty Class 12B locomotives were eventually reboilered with Watson Standard no. 2 boilers. In the process, they were also equipped with Watson cabs with their distinctive slanted fronts, compared to the conventional vertical fronts of their original cabs. Upon reboilering, the unknown original reason for the separate classification was ignored and instead of becoming Class 12BR, the reboilered locomotives were reclassified to Class 12R along with the reboilered Class 12 locomotives.^[1]^[5]^[6]^[7]

Their original Belpaire saturated steam boilers were fitted with Ramsbottom safety valves, while the Watson Standard superheated steam boiler was fitted with Pop safety valves.^[5]^[6]

Service

South African Railways

All thirty locomotives were placed in service on the Cape Midland to work on the mainline out of Port Elizabeth, where they largely remained until being withdrawn after more than sixty years in service. Even though they were not designed to be mixed traffic locomotives, they saw service on both passenger and goods working. Until the Class 15F arrived on the Midland, the mainline was ruled by these locomotives. Later, in spite of their small 51 inches (1,295 millimetres) diameter coupled wheels, they were comfortable at 60 miles per hour (97 kilometres per hour) when employed on the mainline in tandem with the larger Class 15F.^[2]^[3]^[4]^[8]

The Class 12Rs saw mainline work until well into 1969, when the arrival of new Class 33-400 diesel-electrics brought almost fifty years of mainline service to an end. The entire Class gave more than fifty years of service before the first one was withdrawn.^[4]

Even in their twilight years, these locomotives still saw mainline service on the Klipplaat run and as local goods haulers around Port Elizabeth.^[8]

Industrial

For some reason, few Class 12Rs ended up in industrial service despite their evident suitability for such work. Of the ex Class 12B locomotives, only no. 1936 was sold to Enyati Colliery and later became Western Holdings Gold Mine's no. 8.^[7]

Works numbers

The Baldwin works numbers did not run consecutively for the whole order and are shown in the table.^[2]^[3]

Class 12B 4-8-2
Works numbers
SAR no.	Works no.
1931	52476
1932	52558
1933	52559
1934	52583
1935	52584
1936	52649
1937	52650
1938	52651
1939	52690
1940	52691
1941	52692
1942	52693
1943	52712
1944	52713
1945	52723
1946	52724
1947	52754
1948	52755
1949	52756
1950	52757
1951	52758
1952	52759
1953	52760
1954	52761
1955	52762
1956	52763
1957	52764
1958	52765
1959	52766
1960	52767

Preservation

Class	Number	Works nmr	THF / Private	Leaselend / Owner	Current Location
12R	1865	BP 5994	Private		Kimberley Locomotive Depot
12R	1947	BALDWIN 52754	THF	Reefsteamers	Germiston Locomotive Depot
12R	1505	NBL 20176	THF	Umgeni Steam Railway	Kloofstation (Inchaga)
12R	1510	NBL 20812	Private		Creighton Station
12A	2111	NBL 22751	THF		Bloemfontein Locomotive Depot
12AR	1535	NBL 21753	THF	Reefsteamers	Germiston Locomotive Depot

Illustration

Class 12R no. 1939 on the shunt at New Brighton, 31 March 1979

References

Wikimedia Commons has media related to South African Class 12B 4-8-2.

^ ^a ^b ^c ^d 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. p. 780.
^ ^a ^b ^c ^d ^e ^f Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. pp. 10–11, 54–56. ISBN 0869772112.
^ ^a ^b ^c ^d Holland, D. F. (1972). Steam Locomotives of the South African Railways. Vol. 2: 1910-1955 (1st ed.). Newton Abbott, England: David & Charles. pp. 38–41, 82. ISBN 978-0-7153-5427-8.
^ ^a ^b ^c Soul of A Railway, System 3, Part 10: The Midland Main Line, Part 2, Paterson to Alicedale. Captions 4, 31 (Accessed on 15 February 2017)
^ ^a ^b ^c South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. p. 43.
^ ^a ^b ^c South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. 6a-7a, 41, 43.
^ ^a ^b Durrant, AE (1989). Twilight of South African Steam (1st ed.). Newton Abbott: David & Charles. p. 59. ISBN 0715386387.
^ ^a ^b Soul of A Railway, System 3, Part 9: The Midland Main Line, Part 1, Port Elizabeth to Paterson. Captions 14, 52, 58 (Accessed on 5 February 2017)

Locomotives of South Africa

Steam

7' ¼" gauge	East London 0-4-0VB Table Bay 0-4-0ST Table Bay 0-4-0T Table Bay 0-4-0WT
Standard gauge	Cape 0-4-0T Blackie Cape 0-4-2 Cape 2-4-0T CGR 0-4-0ST Aid Natal 0-4-0ST Durban Natal 0-4-0WT Natal Natal 4-4-0T Perseverance
Cape gauge Tank engines	CGR 0-4-0ST 1873 CGR 0-4-0ST 1874 CGR 0-4-0ST 1881 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST CGR 0-6-0T CGR 2-6-0ST 1900 CGR 2-6-0ST 1902 CGR 1st Class 0-4-0ST 1875 CGR 1st Class 0-4-0ST 1876 CGR 1st Class 2-6-0ST CGR 1st Class 4-4-0T CGR 2nd Class 4-4-0T CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack 4-6-4RT CSAR Railmotor Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth 0-4-0ST Kowie Railway 0-6-0T Kowie Railway 4-4-0T Metropolitan & Suburban 4-6-2T NGR 2-6-0T Durban & Pietermaritzburg NGR Class I 2-6-2T NGR Class K 0-4-0ST NGR Class K 0-6-0ST NGR Class K 2-6-0T NZASM 10 Tonner NZASM 13 Tonner NZASM 14 Tonner NZASM 18 Tonner NZASM 19 Tonner NZASM 32 Tonner NZASM 40 Tonner PPR 26 Tonner PPR 35 Tonner Portuguese SAR Class A SAR Class B SAR Class C SAR Class C1 SAR Class C2 SAR Class D SAR Class E SAR Class F SAR Class G SAR Class H SAR Class H1 SAR Class H2 SAR Class J SAR Class K SAR Railmotor SAR Dock 0-4-0ST SAR Dock 0-4-0T SWA 2-8-0T
Cape gauge Tender engines	CGR 1st Class 2-6-0 1876 BP CGR 1st Class 2-6-0 1876 Kitson CGR 1st Class 2-6-0 1879 CGR 1st Class 2-6-0 1891 CGR 1st Class 4-4-0 CGR 1st Class 4-4-0TT CGR 2nd Class 2-6-2TT CGR 3rd Class 4-4-0 1883 CGR 3rd Class 4-4-0 1884 CGR 3rd Class 4-4-0 1889 CGR 3rd Class 4-4-0 1898 CGR 3rd Class 4-4-0 1901 CGR 3rd Class 4-4-0 1903 CGR 4th Class 4-4-2 CGR 4th Class 4-6-0TT 1880 CGR 4th Class 4-6-0TT 1882 CGR 4th Class 4-6-0TT 1882 Joy CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 NGR Havelock NGR Class I SAR Class Exp 1 SAR Class Exp 2 SAR Class Exp 3 SAR Class Exp 4 SAR Class Exp 5 SAR Class Exp 6 SAR Class S SAR Class S1 SAR Class S2 SAR Class 1 SAR Class 1A SAR Class 1B SAR Class 2 SAR Class 2C SAR Class 3 SAR Class 3A SAR Class 3B SAR Class 4 SAR Class 4A SAR Class 5 SAR Class 5A SAR Class 5B SAR Class 6 SAR Class 6A SAR Class 6B SAR Class 6C SAR Class 6D SAR Class 6E SAR Class 6F SAR Class 6G SAR Class 6H SAR Class 6J SAR Class 6K SAR Class 6L SAR Class 6Y SAR Class 6Z SAR Class 7 SAR Class 7A SAR Class 7B SAR Class 7C SAR Class 7D SAR Class 7E SAR Class 7F SAR Class 8 SAR Class 8A SAR Class 8B SAR Class 8C SAR Class 8D SAR Class 8E SAR Class 8F SAR Class 8R SAR Class 8X SAR Class 8Y SAR Class 8Z SAR Class 9 SAR Class 10 SAR Class 10A SAR Class 10B SAR Class 10C SAR Class 10D SAR Class 11 SAR Class 12 SAR Class 12A SAR Class 12B SAR Class 13 SAR Class 14 SAR Class 14A SAR Class 14B SAR Class 14C 1st SAR Class 14C 2nd SAR Class 14C 3rd SAR Class 14C 4th SAR Class 15 SAR Class 15A SAR Class 15B SAR Class 15C SAR Class 15CA SAR Class 15E SAR Class 15F SAR Class 16 SAR Class 16A SAR Class 16B SAR Class 16C SAR Class 16D SAR Class 16DA 1928 SAR Class 16DA 1930 SAR Class 16E SAR Class 17 SAR Class 18 SAR Class 19 SAR Class 19A SAR Class 19B SAR Class 19C SAR Class 19D SAR Class 20 SAR Class 21 SAR Class 23 SAR Class 24 SAR Class 25 SAR Class 25NC SAR Class 26 SAR Katanga SWA 2-8-0
Cape gauge Articulated engines	CGR Fairlie CGR Kitson-Meyer SAR Class FC SAR Class FD SAR Class GA SAR Class GB SAR Class GC SAR Class GCA SAR Class GD SAR Class GDA SAR Class GE SAR Class GEA SAR Class GF SAR Class GG SAR Class GH SAR Class GK SAR Class GL SAR Class GM SAR Class GMA SAR Class GO SAR Class HF SAR Class KM SAR Class MA SAR Class MB SAR Class MC SAR Class MC1 SAR Class MD SAR Class ME SAR Class MF SAR Class MG SAR Class MH SAR Class MJ SAR Class MJ1 SAR Class U
2' 6" gauge	Cape Copper John King & Miner Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Cape Copper Condenser Cape Copper Scotia Namaqua Copper Pioneer Walvis Bay 2-4-2T Hope
2' & 600mm gauges	ACR Class NG-G16A CGR NG 0-4-0T CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T NGR Class N 4-6-2T SAR Dutton SAR NG 0-4-0T SAR Class NG1 SAR Class NG2 SAR Class NG3 SAR Class NG4 SAR Class NG5 SAR Class NG6 SAR Class NG7 SAR Class NG8 SAR Class NG9 SAR Class NG10 SAR Class NG-G11 SAR Class NG-G12 SAR Class NG-G13 SAR Class NG-G14 SAR Class NG15 SAR Class NG-G16 SWA Class Ha SWA Class Hb SWA Class Hc SWA Class Hd SWA Jung SWA Zwillinge

Electric

Amcoal Class E38

Gas-electric

SAR Gas-electric

Diesel

Cape gauge Diesel-electric	PRASA Class Afro 4000 SAR Class DS SAR Class DS1 SAR Class 31-000 SAR Class 32-000 SAR Class 32-200 SAR Class 33-000 SAR Class 33-200 SAR Class 33-400 SAR Class 34-000 SAR Class 34-200 SAR Class 34-400 SAR Class 34-500 SAR Class 34-600 SAR Class 34-800 SAR Class 34-900 SAR Class 35-000 SAR Class 35-200 SAR Class 35-400 SAR Class 35-600 TFR Class 35-800 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 TFR Class 39-200 TFR Class 43-000 TFR Class 44-000 TFR Class 45-000
2' gauge Diesel-electric	SAR Class 91-000
Cape gauge Diesel-hydraulic	SAR Class 61-000
Cape gauge Electro-diesel	Spoornet Class 38-000