Data from "Narrow-Gauge Tank Locomotive for the Bengal-Nagpur Railway", Engineerin (3 July 1903), pp. 3, 6-7, and13; [] sample pages (visited 12 August 2005). See also "Satpura Railway" in Wikipedia at [], last accessed 15 April 2022. Works numbers were 4872-4881 in 1902.
A website devoted to the "Thirty-Inch" gauge -- [] -- is the source for the Satpura Lines attribution in 2005. For seventeen years, Locobase had no more information that would help identify this class. But transmission of Allen Stanley's Rail Data Exchange assembly of "Foreign Builders" allowed me to find the one batch of 2-8-4Ts Sharp, Stewart produced (just before its amalgamation with other Scottish builders into North British Locomotive Company).
Wikipedia's context for construction of this skinny gauge railway--which eventually amassed 1,000 km (621 miles)--was parent Bengal Nagpur Railway's response to the Great Famine of 1876-1878. BNR sought to simplify "access to agricultural and mineral resource of the region, further safeguarding the inhabitants should another famine arise."
Opening the north-south Jubbulpore-Gondia Railway in 1903 marked the tangible effect of such planning. By 1913, this core road, which featured headquarters town Nainpur in the middle, ran for 501 km (311 miles). From Gondia, an extension ran southwest for 349 km (217 miles) to Chanda Fort. Other lines branched northwest from Nagbhir, halfway along the extension.
Very few eight-coupled engines on this gauge sported a rear truck and Locobase shows only two 2-8-4T designs. Kitson's answer to Satpura's demands shows a cab and Belpaire firebox behind a 2-6-2 tank's boiler stretched to accept an additional axle without increasing boiler diameter. The constant-lead radial valve gear assembly seem outsized when compared with the boiler's small dome flanked by two small sandboxes.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 001 |
| Locobase ID | 6747 |
| Railroad | Satpura Lines |
| Country | India |
| Whyte | 2-8-4T |
| Number in Class | 10 |
| Road Numbers | 001-10010 |
| Gauge | 2'6" |
| Number Built | 10 |
| Builder | Sharp, Stewart |
| Year | 1902 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 10.33 / 3.15 |
| Engine Wheelbase (ft / m) | 27.50 / 8.38 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.38 |
| Overall Wheelbase (engine & tender) (ft / m) | 27.50 / 8.38 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 13,888 / 6299 |
| Weight on Drivers (lbs / kg) | 54,656 / 24,792 |
| Engine Weight (lbs / kg) | 87,024 / 39,473 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 23 / 11.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 34 / 864 |
| Boiler Pressure (psi / kPa) | 160 / 1100 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 14.5" x 18" / 368x457 |
| Tractive Effort (lbs / kg) | 15,138 / 6866.49 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.61 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 128 - 2" / 51 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 12.50 / 3.81 |
| Firebox Area (sq ft / m2) | 67 / 6.23 |
| Grate Area (sq ft / m2) | 16.50 |
| Evaporative Heating Surface (sq ft / m2) | 904 / 84.01 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 904 / 84.01 |
| Evaporative Heating Surface/Cylinder Volume | 262.77 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 2640 |
| Same as above plus superheater percentage | 2640 |
| Same as above but substitute firebox area for grate area | 10,720 |
| Power L1 | 3265 |
| Power MT | 526.79 |