Central South African / South African Railways 2-8-2 Locomotives in South_Africa


Class Details by Steve Llanso of Sweat House Media

Class 11 (Locobase 2719)

Data from "The Walschaert Valve Gear and Its Inventor" , The Railway magazine, Volume 15 (October 1904), p. 300.

This Mikado became a standard freight engine for the South African Railways. This was the saturated-boiler design as delivered. To see its later superheated manifestation, refer to Locobase 4385


Class NG15 (Locobase 981)

Data from Wikipedia--[external link] 12/12/12.

These were the earliest 2' Mikados. The first 3 (builder numbers 21905-21907) were delivered in 1931 and 3 more (24475-24477) in 1938. 15 more were delivered after World War II; see NG 15 for 1949.


Class NG5-71 (Locobase 16058)

Data from South African Railways & Harbors 8 - 1941 locomotive diagrams supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange. See also Wikipedia AT [external link], last accessed 1 June 2015. Works numbers were 18578-18583 in 1921

Apparently the three SWA 2-ft-gauge Mikados of 1912 (Locobase 993) were very satisfactory pocket haulers because after World War I, the SAR ordered six more for its SouthWest Africa Mandate in 1921. The design's only difference was a subtle shift in the tube-flue balance from 112 tubes and 14 tubes to 114 tubes and 12 flues.

The Wikipedia entry says that this class worked the 567 km (352 miles) line between Swakopmund on the Atlantic coast to Tsumeb and Grootfontein in South West Africa.

These engines served the SAR well for almost forty years before entering retirement in November 1960.

Principal Dimensions by Steve Llanso of Sweat House Media
Class11NG15NG5-71
Locobase ID2719 981 16,058
RailroadCentral South African (SAR)South African RailwaysSouth African Railways
CountrySouth AfricaSouth AfricaSouth Africa
Whyte2-8-22-8-22-8-2
Number in Class3666
Road Numbers912-94717-19, 117-119NG71 - NG76/18578-18583
Gauge3'6""2'2'
Number Built3666
BuilderNorth BritishHenschel & SohnHenschel & Sohn
Year190419311922
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.13 / 4 9.58 9.56 / 2.91
Engine Wheelbase (ft / m)29.58 / 9.0220.1117.06 / 5.20
Ratio of driving wheelbase to overall engine wheebase 0.44 0.48 0.56
Overall Wheelbase (engine & tender) (ft / m)44.6338.55 / 11.75
Axle Loading (Maximum Weight per Axle) (lbs / kg)14,940
Weight on Drivers (lbs / kg)94,080 / 42,67459,220
Tender Loaded Weight (lbs / kg)107,520 / 48,77069,84057,540 / 26,100
Total Engine and Tender Weight (lbs / kg)235,200 / 106,685151,376131,124 / 59,477
Tender Water Capacity (gals / ML)4800 / 18.1834323432 / 13
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)11 / 106 3.19 / 2.90
Minimum weight of rail (calculated) (lb/yd / kg/m)39 / 19.5025 / 12.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 121933.90 / 86133.90 / 861
Boiler Pressure (psi / kPa)200 / 13.80174 / 12174 / 12
High Pressure Cylinders (dia x stroke) (in / mm)20" x 26" / 508x66015.75" x 17.75" / 400x45115.75" x 17.72" / 400x450
Tractive Effort (lbs / kg)36,833 / 16707.1919,210 / 8713.5219,178 / 8699.00
Factor of Adhesion (Weight on Drivers/Tractive Effort) 2.55 3.08
Heating Ability
Firebox Area (sq ft / m2)138 / 12.836867.79 / 6.30
Grate Area (sq ft / m2)37 / 3.4416.7016.14 / 1.50
Evaporative Heating Surface (sq ft / m2)2092 / 194.42796948 / 88.07
Superheating Surface (sq ft / m2)180145 / 13.47
Combined Heating Surface (sq ft / m2)2092 / 194.429761093 / 101.54
Evaporative Heating Surface/Cylinder Volume221.29198.87237.25
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation740029062808
Same as above plus superheater percentage740034293173
Same as above but substitute firebox area for grate area27,60013,96213,329
Power L1470867696377
Power MT441.301007.98

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