Data from Chief Mechanical Engineer's Office, ndex of Diagrams of Steam Locomotives, South African Railways (Pretoria: 1941), p 23. See also "Class 11 CSAR 700-735 & SAR 912-947-2-8-2-Central South African Railways & South African Railways" on the Preserved British Steam Locomotives website at [] 3ft 6in" , last accessed 1 August 2026.
Locobase 2719 shows the 11th class Mikados as they were delivered with saturated boilers in 1904. At some point, the SAR installed superheaters of relative moderate size. Operationally, the SAR later reduced the train load, notes PBST, "from 1,050 to 900 long tons to reduce running times. This enabled them to run the double trip of 80 miles in each direction."
But the demands for still higher train loads outstripped the 11th class capabilities and more powerful engines took over.
Unlike most other SAR locomotives, the 11th class retained their Belpaire boilers when many older classes received Watson standard boilers.
During the 1940s they were transferred to Kimberley and Port Elizabeth where they headed local freight trains and shunted in rail yards until withdrawn in 1975.
The Preserved site also provide the details of the fifteen engines to enjoy second careers:
Nine served gold mines:
926 became President Brand Gold Mine no. 6
918 became President Brand Gold Mine no. 7 and later Freegold no. 8.
932 became President Brand Gold Mine no. 8.
938 went to President Brand Gold Mine for spare parts
929 became President Steyn Gold Mine no. 6
933 became President Steyn Gold Mine no. 7 and later Freegold no. 7
928 became President Steyn Gold Mine no. 8 and later Freegold no. 5.
944 became Free State Geduld Gold Mine no. 6 and later Freegold no. 6.
945 became Free State Saaiplaas Gold Mine no. 2
921 went to Witbank Coal Mine and later became Tavistock Colliery no. 2.
923 became Western Holdings no. 6.
936 went to ISCOR in Pretoria and later became Tavistock Colliery no. 1.
940 went to ISCOR in Pretoria, later became South Witbank Colliery no. 6 and then Umgala Colliery no. 1 at Utrecht.
943 went to South Witbank Coal Mine and later became Tavistock Colliery no. 3.
946 went to Blue Circle Cement in Lichtenburg and is now part of a static display at the Andries Beyers Farming Museum in Lichtenburg.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 11 |
| Locobase ID | 4385 |
| Railroad | Central South African |
| Country | South Africa |
| Whyte | 2-8-2 |
| Number in Class | 36 |
| Road Numbers | 912-947 |
| Gauge | 3'6" |
| Number Built | |
| Builder | North British |
| Year | 1912 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13.13 / 4 |
| Engine Wheelbase (ft / m) | 29.25 / 8.92 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.45 |
| Overall Wheelbase (engine & tender) (ft / m) | 55.67 / 16.97 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 35,280 / 16,003 |
| Weight on Drivers (lbs / kg) | 139,552 / 63,300 |
| Engine Weight (lbs / kg) | 178,528 / 80,979 |
| Tender Loaded Weight (lbs / kg) | 35,100 / 15,921 |
| Total Engine and Tender Weight (lbs / kg) | 213,628 / 96,900 |
| Tender Water Capacity (gals / ML) | 4800 / 18.18 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 11 / 10 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 58 / 29 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 50 / 1270 |
| Boiler Pressure (psi / kPa) | 190 / 1310 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 20" x 26" / 508x660 |
| Tractive Effort (lbs / kg) | 33,592 / 15237.09 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.15 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 121 - 2.25" / 57 |
| Flues (number - dia) (in / mm) | 21 - 5.5" / 140 |
| Flue/Tube length (ft / m) | 18.02 / 5.49 |
| Firebox Area (sq ft / m2) | 128 |
| Grate Area (sq ft / m2) | 37 / 3.44 |
| Evaporative Heating Surface (sq ft / m2) | 1971 / 183.18 |
| Superheating Surface (sq ft / m2) | 331 / 30.76 |
| Combined Heating Surface (sq ft / m2) | 2302 / 213.94 |
| Evaporative Heating Surface/Cylinder Volume | 208.49 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 7030 |
| Same as above plus superheater percentage | 8014 |
| Same as above but substitute firebox area for grate area | 27,725 |
| Power L1 | 9362 |
| Power MT | 591.60 |