Data from "Diag[ram] 7B, IRS 5' 6" 0-4-2T Passenger Locomotive" supplied by Vinoo Mathur 27 November 2020 post in his Rail Enthusiast series at [], last accessed 3 November 2025; and Dr. Jonathan Smith of Iowa State ([] ) for heating surface and grate area data.
Part of a series of Indian Standard Railway designs created in the mid-1920s to meet Indian railway requirements. This light passenger engine was produced for years by several builders including the Amjer workshops in India. [] -- the website of India's National Rail Museum -- describes this engine as well.
[] notes that these had "...a wider firebox and other improvements to handle low-grade coal."
on this design.
The IRS diagram reveals the use of Timken roller bearings under the "hind truck."
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | IRS/XT |
| Locobase ID | 4264 |
| Railroad | Indian Railways |
| Country | India |
| Whyte | 0-4-2T |
| Number in Class | 77 |
| Road Numbers | |
| Gauge | 5'6" |
| Number Built | 77 |
| Builder | several |
| Year | 1929 |
| Valve Gear | Caprotti |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 6.50 / 1.98 |
| Engine Wheelbase (ft / m) | 14.83 / 4.52 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.44 |
| Overall Wheelbase (engine & tender) (ft / m) | 14.83 / 4.52 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 30,950 / 14,039 |
| Weight on Drivers (lbs / kg) | 67,200 / 30,481 |
| Engine Weight (lbs / kg) | 96,320 / 43,690 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 960 / 3.64 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 2.20 / 2 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 56 / 28 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 51 / 1295 |
| Boiler Pressure (psi / kPa) | 210 / 1430 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 12" x 22" / 305x559 |
| Tractive Effort (lbs / kg) | 11,088 / 5029.44 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 6.06 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | |
| Firebox Area (sq ft / m2) | |
| Grate Area (sq ft / m2) | 14 / 1.30 |
| Evaporative Heating Surface (sq ft / m2) | 577 / 53.61 |
| Superheating Surface (sq ft / m2) | 144 / 13.38 |
| Combined Heating Surface (sq ft / m2) | 721 / 66.99 |
| Evaporative Heating Surface/Cylinder Volume | 200.36 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 2940 |
| Same as above plus superheater percentage | 3528 |
| Same as above but substitute firebox area for grate area | |
| Power L1 | |
| Power MT | |