Data from "0-8-0 Tender-Tank Locomotives for Nigeria", Locomotive Magazine, Volume 61, No 758 (October 1955), p. 167. See also "Engine Nos 51-56", Diagram drafted September 1949 at Ebutemetta. (Thanks to Teemu Koivumaki) (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 3857-3862 in 1955.
LM notes that the design of these eight-coupled locomotives represented Hunlet's standard 17" x 24" 0-8-0T offering (see Locobase 21199). The principal, and significant, difference lay in eliminating the bunker and adding side tanks. They were produced very late in the steam locomotive production era. Hunslet would deliver only fourteen more new-build locomotives.
Side tanks held a total of 1,000 Imperial gallons of water (1,200 US gallons), which together with the 3,800 Imp gal (4,560 US) capacity in the tender, provided 4,800 Imp gal, which allowed "otherwise standard shunting locomotives to operat over far greater distances for much longer periods." Locobase suspects these served NR well in more than shunting roles given their four-axle power able to negotiate "curves of 280 ft with ease" while traveling over 60 lb/yard (30 kg/metre) rail.
As the steam locomotive industry faded in Great Britian, Locobase adds LM's accounting of the variety of special equipment suppliers still needed to outfit even a small engine. Mintex bushes (bushings) served all motion parts, coupling, and connecting rods while Mintex liners could be found in the crossheads, engine axleboxes and tender hornguides. (in 2024, Mintex offered replacement automotive brake parts. A Detroit sight-feed lubricator oiled the cylinders and steam chest; a Wakefield 8-feed mechanical lubricator used the trailing crankpin to lubricate each axlebox.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 51 |
| Locobase ID | 21193 |
| Railroad | Nigerian Railways |
| Country | Nigeria |
| Whyte | 0-8-0T-T |
| Number in Class | 6 |
| Road Numbers | 51-56 |
| Gauge | 3'6" |
| Number Built | 6 |
| Builder | Hunslet Engine Co |
| Year | 1955 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 17.78 / 5.42 |
| Engine Wheelbase (ft / m) | 17.78 / 5.42 |
| Ratio of driving wheelbase to overall engine wheelbase | 1 |
| Overall Wheelbase (engine & tender) (ft / m) | 36.75 / 10.33 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 25,088 / 11,380 |
| Weight on Drivers (lbs / kg) | 105,504 / 47,856 |
| Engine Weight (lbs / kg) | 105,504 / 47,856 |
| Tender Loaded Weight (lbs / kg) | 30,016 / 13,615 |
| Total Engine and Tender Weight (lbs / kg) | 135,520 / 61,471 |
| Tender Water Capacity (gals / ML) | 5760 / 21.82 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 4.40 / 4 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 48 / 1219 |
| Boiler Pressure (psi / kPa) | 180 / 1240 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 18" x 23" / 457x584 |
| Tractive Effort (lbs / kg) | 23,753 / 10774.19 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.44 |
| 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) | 872 / 80.92 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 872 / 80.92 |
| Evaporative Heating Surface/Cylinder Volume | 128.73 |
| 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 | 2842 |
| Power MT | |