Madras & Southern Mahratta class 477
India 1910 25 produced
These Madras & Southern Mahratta locomotives were basically based on the design of the Indian Standards Committee, but as an innovation they were operated with superheated steam and had a slightly reduced boiler pressure. The superheater was of the Schmidt design and had a proportionately larger heating surface than most British-built locomotives. After the four Stephenson locomotives from 1910, a total of 21 from Kitson and Armstrong-Whitworth came in 1919 with slightly altered boiler dimensions and a smaller superheater. Other, almost identical ones went to the Bombay, Baroda & Central India.
Technical data
General
| Property | 477 | 481 |
|---|---|---|
| Built | 1910 | 1919 |
| Manufacturers | Robert Stephenson & Co. | Kitson & Co., Armstrong Whitworth |
| Wheel arrangement | 2-8-0 (Consolidation) | |
| Gauge | 1,676 mm (Indian broad gauge) | |
Dimensions and weights
| Property | 477 | 481 |
|---|---|---|
| Wheelbase | 7.62 m | |
| Total wheelbase | 15.46 m | |
| Service mass | 74.6 t | 74.3 t |
| Adhesion mass | 65.3 t | |
| Total mass | 139.4 t | 139.2 t |
| Rigid wheelbase | 4.88 m | |
| Axle load | 16.3 t | |
| Water capacity | 18,185 l | |
| Fuel capacity | 7.6 t (coal) | |
Boiler
| Property | 477 | 481 |
|---|---|---|
| Grate area | 2.973 m² | |
| Firebox surface | 15.515 m² | 15.608 m² |
| Tube heating surface | 135.081 m² | 131.086 m² |
| Evaporative heating surface | 150.596 m² | 146.694 m² |
| Superheater surface | 34.857 m² | 24.155 m² |
| Total heating surface | 185.5 m² | 170.8 m² |
Power plant
| Property | 477 | 481 |
|---|---|---|
| Driver diameter | 1,435 mm | |
| Boiler pressure | 11 bar | |
| Expansion type | simple expansion | |
| Cylinders | two, 559 x 660 mm | |
Power
| Property | 477 | 481 |
|---|---|---|
| Power source | steam | |
| Estimated power | 820 kW | 802 kW |
| Starting effort | 134.7 kN | |
Calculated values
| Property | 477 | 481 |
|---|---|---|
| Factor of adhesion | 1 : 4.76 | 1 : 4.75 |
| Optimal speed | 37 km/h | |
| Power-to-weight ratio | 11.0 kW/t | 10.8 kW/t |
| Heating Surface Equivalent | 297.9 m² | 273.0 m² |
| Cylinder volume/HSE | 1 : 1,087.40 | 1 : 1,186.33 |
| Adhesive weight/Total | 1 : 1.14 | |
| Tractive force/Heating surface | 1 : 15.17 | 1 : 16.47 |
| Grate area/Heating surface | 1 : 62.38 | 1 : 57.47 |
| Firebox/Tube surface | 1 : 8.71 | 1 : 8.40 |
| Total/Superheater | 1 : 4.32 | 1 : 6.07 |
