ESKOM 0-4-0 Locomotives in South_Africa


Class Details by Steve Llanso of Sweat House Media

Class Stephenson (Locobase 20764)

Data from "Stephenson - circa 1951", The History of the Steam Locomotives that have Served The Electricity Supply Industry in South Africa, Eskom, pp. 41-43, archived at [link], last accessed 23 July 2020, pp. 52-54. Works numbers were 7398, 7677, and 7685.

7677 is the subject of this chapter in ESCOM's history of South Africa's electricity supply industry locomotives. According to the diagram, 7398 served Johannesberg and the Orlando Power Statios, while 7585 went to Swartkops Power Station.

Unfortunately, this stubby, high-boilered switcher did not perform particularly well. The diagram suggests some reasons why. One was the relatively steep incline to the cylinders, which drove on the rear driving axle and turned small drivers. The other is a short wheelbase compared to the boiler and saddle tank's combined height.

EMSCO's history outlined the problems:

"Stephenson has inside steam chests and valve gear making it difficult to work on these parts. She was rather a rough riding engine, she hunted badly, side swinging kicked the track out of line.

'Operating in a yard presented no problems but on a long run she was like a bucking bronco!"

ESCOM's author described Stephenson as "very well-travelled" in a career that eventually led her to Umgeni Steam Railway Museum in Pinetown.

Principal Dimensions by Steve Llanso of Middle Run Media
ClassStephenson
Locobase ID20764
RailroadESKOM
CountrySouth Africa
Whyte0-4-0ST
Number in Class1
Road Numbers
GaugeStd
Number Built1
BuilderStephenson & Hawthorns
Year1951
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 5.50 / 1.68
Engine Wheelbase (ft / m) 5.50 / 1.68
Ratio of driving wheelbase to overall engine wheelbase1
Overall Wheelbase (engine & tender) (ft / m) 5.50 / 1.68
Axle Loading (Maximum Weight per Axle) (lbs / kg)31,360 / 14,225
Weight on Drivers (lbs / kg)62,692 / 28,437
Engine Weight (lbs / kg)62,692 / 28,437
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)840 / 3.18
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 0.95 / 1
Minimum weight of rail (calculated) (lb/yd / kg/m)52 / 26
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)42 / 1067
Boiler Pressure (psi / kPa)165 / 1140
High Pressure Cylinders (dia x stroke) (in / mm)14" x 22" / 356x559
Tractive Effort (lbs / kg)14,399 / 6531.28
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.35
Heating Ability
Tubes (number - dia) (in / mm)124 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 9.85 / 3
Firebox Area (sq ft / m2)55 / 5.11
Grate Area (sq ft / m2) 8.50 / 0.79
Evaporative Heating Surface (sq ft / m2)623 / 57.88
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)623 / 57.88
Evaporative Heating Surface/Cylinder Volume158.94
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1403
Same as above plus superheater percentage1403
Same as above but substitute firebox area for grate area9075
Power L12646
Power MT186.10

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