Data from "Engine Nos 70-99", Diagram drafted April 1953 at Ebutemetta. (Many thanks to Teemu Koivumaki for his 19 August 2024 email supplying key information for several Nigerian Railways classes and for finding this diagram and emailing it to me on 29 August 2024.) Works numbers were 3345-3355 in 1946; 3552-3555, 3625-3636 in 1949.
NR's 1953 diagram shows three Hawthorn-built six-coupled tanks numbered 71-73 from 1925-1926, which apparently inspired the much larger Hunslet contracts beginning at the end of World War II. These are clearly shunters, given the small fuel and water capacities and small drivers. But their tractive effort suggests a useful pulling power.
Locobase suspects the NR renumbered engine 70 to 100 sometime later than 1949 to group all the Hunslets together.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 71 |
| Locobase ID | 21199 |
| Railroad | Nigerian Railways |
| Country | Nigeria |
| Whyte | 0-8-0T |
| Number in Class | 30 |
| Road Numbers | 71-100 |
| Gauge | 3'6" |
| Number Built | 30 |
| Builder | Hunslet Engine Co |
| Year | 1946 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13.40 / 4.08 |
| Engine Wheelbase (ft / m) | 13.40 / 4.08 |
| Ratio of driving wheelbase to overall engine wheelbase | 1 |
| Overall Wheelbase (engine & tender) (ft / m) | 13.40 / 4.08 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 27,440 / 12,447 |
| Weight on Drivers (lbs / kg) | 108,864 / 48,892 |
| Engine Weight (lbs / kg) | 108,864 / 48,892 |
| Tender Loaded Weight (lbs / kg) | 30,016 / 13,615 |
| Total Engine and Tender Weight (lbs / kg) | 138,880 / 62,507 |
| Tender Water Capacity (gals / ML) | 1200 / 4.55 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 2.20 / 2 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 45 / 22.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 42.75 / 1086 |
| Boiler Pressure (psi / kPa) | 180 / 1240 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 18" x 23" / 457x584 |
| Tractive Effort (lbs / kg) | 26,670 / 12097.32 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.08 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 171 - 1.75" / 44 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 9.96 / 3.04 |
| Firebox Area (sq ft / m2) | 93 / 8.64 |
| Grate Area (sq ft / m2) | 13.35 / 1.24 |
| Evaporative Heating Surface (sq ft / m2) | 884 / 82.13 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 884 / 82.13 |
| Evaporative Heating Surface/Cylinder Volume | 130.50 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 2403 |
| Same as above plus superheater percentage | 2403 |
| Same as above but substitute firebox area for grate area | 16,740 |
| Power L1 | 2554 |
| Power MT | 206.89 |