South African Class MC1 2-6-6-0

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South African Class MC1 2-6-6-0
Class MC1 (2-6-6-0).jpg
SAR Class MC1 with engine driver Mr. Kok, c. 1930
Type and origin
Power typeSteam
DesignerNorth British Locomotive Company
BuilderNorth British Locomotive Company
Serial number20442-20456
Build date1913-1914
Total produced15
 • Whyte2-6-6-0 (Denver)
 • UIC(1'C)Chv4
Driver3rd & 6th coupled axles
Gauge3 ft 6 in (1,067 mm) Cape gauge
Leading dia.28 12 in (724 mm)
Coupled dia.45 12 in (1,156 mm)
Tender wheels34 in (864 mm)
Wheelbase60 ft (18,288 mm)
 • Engine33 ft 5 in (10,185 mm)
 • Coupled8 ft 4 in (2,540 mm) per unit
 • Tender16 ft 9 in (5,105 mm)
 • Tender bogie4 ft 7 in (1,397 mm)
 • Over couplers68 ft 5 18 in (20,857 mm)
Height12 ft 5 316 in (3,789 mm)
Axle load16 LT 4 cwt (16,460 kg)
 • Leading7 LT 19 cwt (8,078 kg)
 • 1st coupled13 LT 16 cwt (14,020 kg)
 • 2nd coupled15 LT 3 cwt (15,390 kg)
 • 3rd coupled15 LT 7 cwt (15,600 kg)
 • 4th coupled14 LT 19 cwt (15,190 kg)
 • 5th coupled14 LT 10 cwt (14,730 kg)
 • 6th coupled16 LT 4 cwt (16,460 kg)
 • Tender bogieBogie 1: 27 LT 10 cwt (27,940 kg)
Bogie 2: 23 LT 11 cwt (23,930 kg)
 • Tender axle13 LT 15 cwt (13,970 kg)
Adhesive weight89 LT 19 cwt (91,390 kg)
Loco weight97 LT 18 cwt (99,470 kg)
Tender weight51 LT 1 cwt (51,870 kg)
Total weight148 LT 19 cwt (151,300 kg)
Tender typeMP1 (2-axle bogies)
Fuel typeCoal
Fuel capacity10 LT (10.2 t)
Water cap4,250 imp gal (19,300 l)
Firebox typeRound-top
 • Firegrate area42.5 sq ft (3.95 m2)
 • Pitch7 ft 6 in (2,286 mm)
 • Diameter5 ft 8 in (1,727 mm)
 • Tube plates16 ft 2 34 in (4,947 mm)
 • Small tubes152: 2 14 in (57 mm)
 • Large tubes27: 5 38 in (137 mm)
Boiler pressure200 psi (1,379 kPa)
Safety valveRamsbottom
Heating surface2,214 sq ft (205.7 m2)
 • Tubes2,060 sq ft (191 m2)
 • Firebox154 sq ft (14.3 m2)
 • Heating area580 sq ft (54 m2)
High-pressure cylinder18 in (457 mm) bore
26 in (660 mm) stroke
Low-pressure cylinder28 12 in (724 mm) bore
26 in (660 mm) stroke
Valve gearWalschaerts
Valve typeHP Piston, LP Slide
CouplersJohnston link-and-pin
Performance figures
Tractive effort46,414 lbf (206.46 kN) @ 50%
OperatorsSouth African Railways
ClassClass MC1
Number in class15
First run1914

The South African Railways Class MC1 2-6-6-0 of 1914 was a steam locomotive.

In 1914 the South African Railways placed fifteen Class MC1 Mallet articulated compound steam locomotives with a 2-6-6-0 wheel arrangement in service.[1][2]


Orders for an improved version of the Class MC were placed with the North British Locomotive Company in 1913. When the fifteen locomotives were delivered and placed in service in May 1914, they were designated Class MC1 and numbered in the range from 1634 to 1648.[1][2][3][4]


The Class MC1 were duplicates of the Class MC in most respects, to the extent that the majority of spare parts for the two classes were interchangeable. Improvements consisted mainly of 12 inch (13 millimetres) larger diameter high-pressure and low-pressure cylinders and a redesigned boiler which included a superheater instead of the saturated steam boiler of the Class MC. The high-pressure cylinders of the hind engine unit were equipped with piston valves while the low-pressure cylinders of the front engine unit were equipped with slide valves.[1][2][3]

An externally obvious difference was the main steam pipes from the dome to the high-pressure cylinders, which was no longer arranged vertically down directly to the cylinders along the outside of the boiler, but internally via the superheater in the smokebox and from there along the underside of the running boards back to the cylinders. The result was a much better performing locomotive with an increased tractive effort brought about by the larger cylinders.[1][2][3]

The locomotives were delivered with Type MP1 tenders with a coal capacity of 10 long tons (10.2 tonnes) and a water capacity of 4,250 imperial gallons (19,300 litres). The same tender was used by altogether sixteen locomotive classes, but those of the Class MC1 were fitted with a radial type of drawgear.[3]


When the coupled wheel tyres had to be renewed, the diameter of the wheels was increased from 45 12 inches (1,156 millimetres) to 46 inches (1,168 millimetres). This reduced the tractive effort from 46,414 pounds-force (206 kilonewtons) at 50% of boiler pressure to 45,900 pounds-force (204 kilonewtons). Unlike all other locomotive types where the SAR reported tractive effort at 75% of boiler pressure, it followed an ultra-conservative practice of reporting that of all Mallet locomotives at 50%.[3][5]


The Class MC1 was placed in service on the coal line from Witbank to Germiston. In later years, some also saw service on the Natal mainline and the Cape Midland System. A number of them were transferred to the Cape Western System where they served as banking engines up the Hex River Railpass between De Doorns and Touws River.[1][2][5][6]

The locomotives were all finally withdrawn from service and scrapped during 1937.[3]


The main picture shows driver Kok with his locomotive, c. 1930, while the following serve to illustrate both sides of the locomotive as well as the lined livery which was in use on the SAR when the locomotives were introduced.


  1. ^ a b c d e Holland, D. F. (1972). Steam Locomotives of the South African Railways. 2: 1910-1955 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 21–22. ISBN 978-0-7153-5427-8.
  2. ^ a b c d e Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 85. ISBN 0869772112.
  3. ^ a b c d e f 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. p. 349.
  4. ^ North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser
  5. ^ a b Soul of A Railway, System 7, Western Transvaal, based in Johannesburg, Part 21: Witbank Line by Les Pivnic, Eugene Armer, Peter Stow and Peter Micenko. Caption 3. (Accessed on 4 May 2017)
  6. ^ Soul of A Railway - System 1 – Part 3: Wellington to Touws River – Caption 26 (Accessed on 27 November 2016)