Madagascar Railway No. 35 to 40 and 61 to 68
The first five Mallets for the Madagascar Railway were built in 1916 by Baldwin and carried the works numbers 44331 to 44334, 44609 and 44610. They had to be suitable for the winding lines between the east coast and the capital Antananarivo. Requirements included the ability to haul a 110-tonne train up a 2.5 percent incline at 12 km/h. They had two groups of two axles each and water tanks along the sides of the boiler, while the wood was stored in an additional tender. A Belpaire firebox was used to better utilize the heat of the wood.
The six locomotives of the original Baldwin variant were numbered 35 to 40. Nine years later, they ordered eight more with a superheater. Now, the order went to SACM in France. These locomotives carried the works numbers 7391 to 7398 and were numbered 61 to 68 by the railway. The high pressure cylinders now had a diameter that was 20 mm bigger.
Technical data
General
| Property | 35-40 | 61-68 |
|---|---|---|
| Built | 1916 | 1925 |
| Manufacturers | Baldwin | SACM |
| Wheel arrangement | 0-4-4-0T (Four Coupled Mallet) | |
| Gauge | 1,000 mm (Meter gauge) | |
Dimensions and weights
| Property | 35-40 | 61-68 |
|---|---|---|
| Wheelbase | 4.67 m | |
| Total wheelbase | 9.12 m | 9.20 m |
| Service mass | 32 t | 32.6 t |
| Adhesion mass | 32 t | 32.6 t |
| Total mass | 42.5 t | 43.5 t |
| Rigid wheelbase | 1.40 m | |
| Axle load | 8 t | 8.2 t |
| Water capacity | 1,900 l | 2,100 l |
| Fuel capacity | 3 t (wood) | |
Boiler
| Property | 35-40 | 61-68 |
|---|---|---|
| Grate area | 1.19 m² | |
| Firebox surface | 6.44 m² | 6.45 m² |
| Tube heating surface | 64.82 m² | 50.24 m² |
| Evaporative heating surface | 71.26 m² | 56.69 m² |
| Total heating surface | 71.3 m² | 73.5 m² |
| Superheater surface | 16.85 m² | |
Power plant
| Property | 35-40 | 61-68 |
|---|---|---|
| Driver diameter | 1,010 mm | |
| Boiler pressure | 12 bar | |
| Expansion type | simple expansion | |
| Cylinders | four, 280 x 500 mm | four, 300 x 500 mm |
Power
| Property | 35-40 | 61-68 |
|---|---|---|
| Power source | steam | |
| Estimated power | 250 kW (340 PS) | 300 kW (408 PS) |
| Starting effort | 79.2 kN | 90.9 kN |
Calculated values
| Property | 35-40 | 61-68 |
|---|---|---|
| Factor of adhesion | 1 : 3.96 | 1 : 3.52 |
| Optimal speed | 19 km/h | 21 km/h |
| Power-to-weight ratio | 7.8 kW/t | 9.2 kW/t |
| Heating Surface Equivalent | 103.5 m² | 122.6 m² |
| Cylinder volume/HSE | 1 : 1,190.32 | 1 : 1,152.74 |
| Adhesive weight/Total | 1 : 1.00 | |
| Tractive force/Heating surface | 1 : 23.21 | 1 : 25.81 |
| Grate area/Heating surface | 1 : 59.88 | 1 : 61.80 |
| Firebox/Tube surface | 1 : 10.07 | 1 : 7.79 |
| Total/Superheater | 1 : 3.36 | |