Data from "Class PT/S B.E.S.A 5-6 Gauge, 2-6-4 Passenger Locomotive Diagram No. 29" supplied by Vindoo Mathur in the 27 November 2020 entry in his railenthusiast series at [], last accessed 9 November 2025.
Locobase 4248 describes the 1910 variant of the British Engineering Standards Association (BESA) series of standard designs for Indian railways implemented in the first decade of the 20th century. Slightly more than a decade later, the Bombay, Baroda & Central India updated the BESA design with the assistance of Armstrong Whitworth by enlarging the cylinders and fitting a superheater. The Belpaire firebox's grate area increased as did total direct heating surface area.
Six years later, the BB&CI sold seven of the class to the Indian State Railways.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | BESA/PTS |
| Locobase ID | 21278 |
| Railroad | Indian State |
| Country | India |
| Whyte | 2-6-4T |
| Number in Class | 7 |
| Road Numbers | 520-521, 515, 519, 530-531 |
| Gauge | 5'6" |
| Number Built | |
| Builder | ISR |
| Year | 1922 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13 / 3.96 |
| Engine Wheelbase (ft / m) | 34.25 / 10.44 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.38 |
| Overall Wheelbase (engine & tender) (ft / m) | 34.25 / 10.44 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 39,872 / 18,086 |
| Weight on Drivers (lbs / kg) | 119,504 / 54,206 |
| Engine Weight (lbs / kg) | 197,120 / 89,412 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 3000 / 11.36 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 5.78 / 5.30 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 66 / 33 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 61.50 / 1562 |
| Boiler Pressure (psi / kPa) | 160 / 1090 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 20" x 26" / 508x660 |
| Tractive Effort (lbs / kg) | 22,998 / 10431.73 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 5.20 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 121 - 2" / 51 |
| Flues (number - dia) (in / mm) | 21 - 5.25" / 133 |
| Flue/Tube length (ft / m) | 11.37 / 3.47 |
| Firebox Area (sq ft / m2) | 150 / 13.94 |
| Grate Area (sq ft / m2) | 27 / 2.51 |
| Evaporative Heating Surface (sq ft / m2) | 1195 / 111.02 |
| Superheating Surface (sq ft / m2) | 260 / 24.15 |
| Combined Heating Surface (sq ft / m2) | 1455 / 135.17 |
| Evaporative Heating Surface/Cylinder Volume | 126.40 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 4320 |
| Same as above plus superheater percentage | 5098 |
| Same as above but substitute firebox area for grate area | 28,320 |
| Power L1 | 7433 |
| Power MT | 411.37 |