Data from "Sheet No: 39 NR (metre gauge) 0-6-2" supplied by Vinoo Mathur 27 November 2020 post in his Rail Enthusiast series at [], last accessed 3 November 2025; Krupp im Dienst der Dampflokomotive (Essen, Germany: 1940), p. 101. Krupp's works numbers for the 41 YFs it delivered in 1930. Eastern Bengal received the first five (works number 1117-1121 in July 1930). The next fiften went to the Bombay,Baroda & Central Indian (works 1122-1130 in August 1930 1131-1136 in May-June). Assam Bengal's quartet (1137-1140 in June), and South Indian acquired sixteen (works 1141-1144 in May, 1145-1149 in July, and 1150-1157 in August.)
Part of a series of designs grouped under Indian Railway Standard (IRS) created in the mid-1920s to meet Indian railway requirements. [] notes that these had "...a wider firebox and other improvements to handle low-grade coal."
The wheel arrangement for the traversing trailing truck, kept a high percentage of the weight on the drivers while allowing the engine to negotiate narrow-gauge, branch-line curves. Unlike most 0-6-2s, which mounted water tanks on the running board, YFs drew a tender that carried more coal and water.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | IRS/YF |
| Locobase ID | 21277 |
| Railroad | Indian Railways |
| Country | India |
| Whyte | 0-6-2 |
| Number in Class | |
| Road Numbers | |
| Gauge | Metre |
| Number Built | |
| Builder | Krupp |
| Year | 1930 |
| Valve Gear | Stephenson-Belpaire |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 8 / 2.44 |
| Engine Wheelbase (ft / m) | 15.50 / 4.72 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.52 |
| Overall Wheelbase (engine & tender) (ft / m) | 32.87 / 10.02 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 18,144 / 8230 |
| Weight on Drivers (lbs / kg) | 54,208 / 24,588 |
| Engine Weight (lbs / kg) | 72,750 / 32,999 |
| Tender Loaded Weight (lbs / kg) | 54,560 / 24,748 |
| Total Engine and Tender Weight (lbs / kg) | 127,310 / 57,747 |
| Tender Water Capacity (gals / ML) | 2402 / 9.10 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 4.40 / 4 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 30 / 15 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 43 / 1092 |
| Boiler Pressure (psi / kPa) | 160 / 1090 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 14" x 22" / 356x559 |
| Tractive Effort (lbs / kg) | 13,638 / 6186.10 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.97 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 70 - 1.75" / 44 |
| Flues (number - dia) (in / mm) | 13 - 5.25" / 133 |
| Flue/Tube length (ft / m) | 11 / 3.35 |
| Firebox Area (sq ft / m2) | 80.70 / 7.50 |
| Grate Area (sq ft / m2) | 17.87 / 1.66 |
| Evaporative Heating Surface (sq ft / m2) | 641 / 59.55 |
| Superheating Surface (sq ft / m2) | 136 / 12.63 |
| Combined Heating Surface (sq ft / m2) | 777 / 72.18 |
| Evaporative Heating Surface/Cylinder Volume | 163.53 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 2859 |
| Same as above plus superheater percentage | 3374 |
| Same as above but substitute firebox area for grate area | 15,236 |
| Power L1 | 6636 |
| Power MT | 809.65 |