South African Class MC1 2-6-6-0

South African Class MC1 2-6-6-0

300px SAR Class MC1 with engine driver Mr. Kok, c. 1930

Type and origin Power type Steam Designer North British Locomotive Company Builder North British Locomotive Company Serial number 20442-20456 Build date 1913-1914 Total produced 15

Specifications Configuration 2-6-6-0 (Denver) Driver axle 3rd & 6th coupled axles Gauge 3 ft 6 in (1,067 mm) Cape gauge Leading dia Coupled dia Tender wheels 34 in (864 mm) Wheelbase 60 ft (18,288 mm)  • Engine 33 ft 5 in (10,185 mm)  • Coupled 8 ft 4 in (2,540 mm) per unit  • Tender 16 ft 9 in (5,105 mm)  • Tender bogie 4 ft 7 in (1,397 mm) Length:  • Over couplers Height Axle load  • Leading  • 1st coupled  • 2nd coupled  • 3rd coupled  • 4th coupled  • 5th coupled  • 6th coupled  • Tender bogie Bogie 1: Bogie 2:  • Tender axle Adhesive weight Loco weight Tender weight Loco & tender weight Tender type MP1 (2-axle bogies) Fuel type Coal Fuel capacity 10 LT (10.2 t) Water cap Boiler:  • Pitch 7 ft 6 in (2,286 mm)  • Diameter 5 ft 8 in (1,727 mm)  • Tube plates  • Small tubes 152:  • large tubes 27:  • Firebox type Round-top Boiler pressure 200 psi (1,379 kPa) Safety valve Ramsbottom Firegrate area 42.5 sq ft (3.95 m2) Heating surface 2,214 sq ft (205.7 m2)  • Tubes 2,060 sq ft (191 m2)  • Firebox 154 sq ft (14.3 m2) Superheater:  • Heating area 580 sq ft (54 m2) Cylinders Four High-pressure cylinder size 18 in (457 mm) bore 26 in (660 mm) stroke Low-pressure cylinder size bore 26 in (660 mm) stroke Valve gear Walschaerts Couplers Bell link-and-pin

Performance figures Tractive effort 46,414 lbf (206.46 kN) @ 50%

Career Operators South African Railways Class Class MC1 Number in class 15 Numbers 1634-1648 Delivered 1914 First run 1914 Withdrawn 1937

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.

Manufacturer

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.

Characteristics

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 a redesigned boiler which included a superheater, instead of the saturated steam boiler of the Class MC, and larger diameter high pressure and low pressure cylinders.

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.

The locomotives were delivered with Type MP1 tenders with a coal capacity of 10 long tons (10.2 tonnes) and a water capacity of . The same tender was used by altogether fifteen other locomotive Classes, but those of the Class MC1 were fitted with the radial type of drawgear.

Modifications

When the coupled wheel tyres had to be renewed, the diameter of the wheels was increased from 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).

Service

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.

They locomotives were all finally withdrawn from service and scrapped during 1937.

Illustration

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.

• SAR Class MC1 1635 (2-6-6-0).jpg

  No. 1635 in service as banking engine at De Doorns, c. 1930

• SAR Class MC1 1642 (2-6-6-0).jpg

  Works picture of Class MC1 no. 1642, c. 1914