Data from Ahrons (1927). See also R A S Hennessey, Atlantic: The Well-Beloved Engine (Stroud, Gloucestershire: Tempus Publishing Co, Ltd, 2002);"New Locomotive Types: Bengal-Nagpur Railway", Railway Times, Volume XCIV [94], No 14 (3 October 1908), pp. 370-371; and "Calcutta-Madras Mail Trains, Bengal Nagpur Ry", Locomotive Magazine, Volume XXI [21] (15 July 1915), p. 146.
Based on the British Engineering Standards Association Atlantic design, these Bengal Nagpur locomotives offered a twist. As Roger Hennessey puts it, the BN was "...a thorn of individualism in the side of the standardisers [and] insisted on a 4-cylinder de Glehn compound version." The first pair were supplied on a trial basis and could be returned within 12 months if the BNR was not satisfied.
The BNR was more than satisfied. The Ks were certainly bigger than most engines of that arrangement in Great Britain at the time. De Glehns put their HP cylinders outside to drive the second axle while the inside LP cylinders drove the leading axle. These had a Belpaire firebox offering a heating surface of 153 sq ft.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | K |
| Locobase ID | 3026 |
| Railroad | Bengal Nagpur |
| Country | India |
| Whyte | 4-4-2 |
| Number in Class | 15 |
| Road Numbers | |
| Gauge | 5'6" |
| Number Built | 15 |
| Builder | North British |
| Year | 1907 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 7 / 2.13 |
| Engine Wheelbase (ft / m) | 28 / 8.53 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.25 |
| Overall Wheelbase (engine & tender) (ft / m) | 50.87 / 15.51 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 38,640 / 17,781 |
| Weight on Drivers (lbs / kg) | 78,400 / 35,562 |
| Engine Weight (lbs / kg) | 161,728 / 73,359 |
| Tender Loaded Weight (lbs / kg) | 90,160 / 40,896 |
| Total Engine and Tender Weight (lbs / kg) | 251,888 / 114,255 |
| Tender Water Capacity (gals / ML) | 4200 / 15.91 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 6.60 / 6 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 65 / 32.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 78 / 1981 |
| Boiler Pressure (psi / kPa) | 220 / 1520 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 13" x 26" / 330x660 |
| Low Pressure Cylinders (dia x stroke) (in / mm) | 21.5" x 26" / 546x660 |
| Tractive Effort (lbs / kg) | 15,428 / 6998.03 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.08 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 195 - 2.125" / 54 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 14.75 / 4.50 |
| Firebox Area (sq ft / m2) | 153 / 14.21 |
| Grate Area (sq ft / m2) | 31.70 / 2.95 |
| Evaporative Heating Surface (sq ft / m2) | 1899 / 176.42 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 1899 / 176.42 |
| Evaporative Heating Surface/Cylinder Volume | 475.43 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 6974 |
| Same as above plus superheater percentage | 6974 |
| Same as above but substitute firebox area for grate area | 33,660 |
| Power L1 | 6974 |
| Power MT | 392.22 |