South African Class MC 2-6-6-0

SAR Class MC no. 1608, c. 1912

Type and origin
Power type	Steam
Designer	American Locomotive Company
Builder	North British Locomotive Company
Serial number	19577-19586
Model	NGR Mallet
Build date	1912
Total produced	10

Specifications
Configuration	2-6-6-0 (Denver)
Driver	3rd & 6th coupled axles
Gauge	3 ft 6 in (1,067 mm) Cape gauge
Leading dia.	28 ¹⁄₂ in (724 mm)
Coupled dia.	45 ¹⁄₂ in (1,156 mm)
Tender wheels	30 in (762 mm)
Wheelbase	59 ft 3 in (18,059 mm)
• Engine	33 ft 5 in (10,185 mm)
• Coupled	8 ft 4 in (2,540 mm) per unit
• Tender	16 ft 6 in (5,029 mm)
• Tender bogie	4 ft 6 in (1,372 mm)
Length:
• Over couplers	66 ft 9 ³⁄₄ in (20,364 mm)
Height	12 ft 5 ³⁄₁₆ in (3,789 mm)
Axle load	14 LT 13 cwt (14,890 kg)
• Leading	8 LT 15 cwt (8,890 kg)
• 1st coupled	14 LT 5 cwt (14,480 kg)
• 2nd coupled	14 LT 5 cwt (14,480 kg)
• 3rd coupled	14 LT 7 cwt (14,580 kg)
• 4th coupled	14 LT 10 cwt (14,730 kg)
• 5th coupled	14 LT 11 cwt (14,780 kg)
• 6th coupled	14 LT 13 cwt (14,890 kg)
• Tender bogie	Bogie 1: 21 LT 14 cwt (22,050 kg) Bogie 2: 21 LT 16 cwt (22,150 kg)
• Tender axle	10 LT 18 cwt (11,070 kg)
Adhesive weight	86 LT 11 cwt (87,940 kg)
Loco weight	95 LT 6 cwt (96,830 kg)
Tender weight	43 LT 10 cwt (44,200 kg)
Total weight	138 LT 16 cwt (141,000 kg)
Tender type	TM (2-axle bogies)
Fuel type	Coal
Fuel capacity	8 LT 5 cwt (8.4 t)
Water cap	4,000 imp gal (18,200 l)
Firebox type	Round-top
• Firegrate area	42.5 sq ft (3.95 m²)
Boiler:
• Pitch	7 ft 6 in (2,286 mm)
• Diameter	5 ft 8 in (1,727 mm)
• Tube plates	16 ft 2 ³⁄₄ in (4,947 mm)
• Small tubes	258: 2 ¹⁄₄ in (57 mm)
Boiler pressure	200 psi (1,379 kPa)
Safety valve	Ramsbottom
Heating surface	2,616 sq ft (243.0 m²)
• Tubes	2,462 sq ft (228.7 m²)
• Firebox	154 sq ft (14.3 m²)
Cylinders	Four
High-pressure cylinder	17 ¹⁄₂ in (444 mm) bore 26 in (660 mm) stroke
Low-pressure cylinder	28 in (711 mm) bore 26 in (660 mm) stroke
Valve gear	Walschaerts
Couplers	Bell link-and-pin

Performance figures
Tractive effort	44,810 lbf (199.3 kN) @ 50%

Career
Operators	South African Railways
Class	Class MC
Number in class	10
Numbers	1607-1616
Delivered	1912
First run	1912
Withdrawn	1933

The South African Railways Class MC 2-6-6-0 of 1912 was a steam locomotive.

In 1912, the South African Railways placed ten Class MC Mallet articulated compound steam locomotives with a 2-6-6-0 wheel arrangement in service in Natal.^[1]^[2]^[3]^[4]

Manufacturer

In order to augment the Mallet locomotive fleet operating across the more difficult sections of the Natal mainline, the South African Railways (SAR) placed an order with the North British Locomotive Company for ten compound steam locomotives which were very similar to the Class MB. They were delivered and placed in service in May 1912, designated Class MC and numbered in the range from 1607 to 1616.^[1]^[2]^[3]^[4]^[5]

Compounding

In a compound locomotive, steam is expanded in phases. After being expanded in a high pressure cylinder and having then lost pressure and given up part of its heat, it is exhausted into a larger volume low pressure cylinder for secondary expansion, after which it is exhausted through the smokebox.^[6]

In the compound Mallet locomotive, the rear set of coupled wheels are driven by the smaller high pressure cylinders, which are fed steam from the steam dome. Their spent steam is then fed to the larger low pressure cylinders, which drive the front set of coupled wheels. By comparison, in the more usual arrangement of simple expansion, steam is expanded just once in any one cylinder before being exhausted through the smokebox.^[1]^[3]

Characteristics

Like the previous Mallets, these ten compound locomotives had Walschaerts valve gear and used saturated steam. Their Type TM tenders were the same as those of the Classes 3 and 3B, with a coal capacity of 8 long tons 5 hundredweight (8.4 tonnes) and a water capacity of 4,000 imperial gallons (18,200 litres), but they differed little from the previous Mallets in size, power and performance and may for all intents and purposes also have been classified as Class MB. It would seem that, compared to the Cape Government Railways, which tended to group locomotives in the same Class which were dissimilar even to the extent of having different wheel arrangements, the early SAR at times took locomotive classification to the other extreme.^[1]^[3]

Unlike the Class MB, on which the sandboxes were placed on top of the boiler in accordance with American practice, the sandboxes of the Class MC were arranged on a different system, the advantages of which were questionable. The sandboxes for the hind engine unit were secured to the running board, just to the rear of the high-pressure cylinders, while those for the front engine unit were placed on the upper sides of the boiler, just to the rear of the smokebox.^[2]

Superheating

The Class MC were satisfactory locomotives, but, like the earlier Mallet compounds, they would have performed better if they had been superheated. Two of them, numbers 1612 and 1615, were later equipped with new boilers and superheaters and their coupled wheels were retyred to a diameter of 46 inches (1,168 millimetres). No others were modified in this manner.^[1]^[2]^[3]

Service

The Class MC joined the Class MA and MB fleet on the Natal mainline, working heavy coal trains between Estcourt and Highlands. In later years, some were transferred to the Cape Western System, where they served into the 1930s as banking locomotives up the Hex River Railpass between De Doorns and Touws River. Others were transferred to the Witwatersrand for general service and to haul coal on the Witbank line. They were withdrawn from service during 1933.^[1]^[2]^[3]

References

1 2 3 4 5 6 Holland, D.F. (1972). Steam Locomotives of the South African Railways, Volume 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 21–22. ISBN 978-0-7153-5427-8.
1 2 3 4 5 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, May 1945. pp. 347-350, 356.
1 2 3 4 5 6 Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 85. ISBN 0869772112.
1 2 Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 9, 12, 15, 46 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)
↑ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
↑ Compounding Steam Engines

Wikimedia Commons has media related to South African Class MC (2-6-6-0).

Locomotives of South Africa

Steam

7' ¼" gauge	East London Harbour 0-4-0 Table Bay Harbour 0-4-0ST Table Bay Harbour 0-4-0T Table Bay Harbour 0-4-0WT

4' 8½" 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

3' 6" gauge Tank engines	CGR 0-4-0ST 1873 CGR 0-4-0ST 1874 CGR 0-4-0ST 1881 Coffee Pot CGR 0-6-0ST 1902 CGR 0-6-0T 1876 Back-to-Back 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 1876 CGR 1st Class 4-4-0T 1875 CGR 2nd Class 4-4-0T 1882 CGR 3rd Class 2-6-0T CGR Railmotor CSAR Class C CSAR Class E CSAR Rack CSAR Railmotor DSWA Eight-Coupled Tank 2-8-0T Durban's Congella Durban's Edward Innes Durban's John Milne Durban's Sir Albert Port Elizabeth Harbour 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 0-4-0ST 1903 SAR 0-4-0T no. 69 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 Clayton

3' 6" gauge Tender engines	CGR 1st Class 2-6-0 1876 Beyer, Peacock 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 1879 CGR 1st Class 4-4-0TT 1881 CGR 2nd Class 2-6-2TT 1875 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 Joy 1882 CGR 4th Class 4-6-0TT 1884 CGR 5th Class 4-6-0 1890 CGR 5th Class 4-6-0 1891 DSWA Eight-Coupled Tender 2-8-0 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 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

3' 6" 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 0-6-0T 1871 Cape Copper Britannia Cape Copper Caledonia Cape Copper Clara Cape Copper Condenser Cape Copper Scotia Namaqua Copper Pioneer

2' & 600mm gauges	ACR Class NG-G16A CGR NG 0-6-0T CGR NG 4-6-2T CGR Type A 2-6-4T CGR Type C 0-4-0T DSWA Class Ha DSWA Class Hb DSWA Class Hc DSWA Class Hd DSWA Jung DSWA Zwillinge NGR Class N 4-6-2T SAR Dutton SAR NG 0-4-0T 1899 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

Electric

Amcoal Class E38

Gas-electric

Gas-electric

Diesel

3' 6" 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 SAR Class 36-000 SAR Class 36-200 SAR Class 37-000 Spoornet Class 39-000 TFR Class 35-800 TFR Class 39-200 TFR Class 43-000 TFR Class 44-000

2' gauge Diesel-electric	SAR Class 91-000

3' 6" gauge Diesel-hydraulic	SAR Class 61-000

3' 6" gauge Electro-diesel	Spoornet Class 38-000

South African steam locomotive tenders

Cape gauge	Type LP Type MP1 Type MR Type SH Type SK Type TJ Type TL Type TM Type WE Type WG Type XC Type XC1 Type XD Type XE Type XE1 Type XF Type XF2 Type XJ Type XM Type XM1 Type XM2 Type XM3 Type XM4 Type XP1 Type XS Type YB Type YC Type YE Type YE1 Type ZA Type ZB Type ZC Type ZE

List of South African locomotive classes South African locomotive history

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