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Northern Pacific classes WA, WB and W-1
The Northern Pacific was the first US railroad to purchase a significant number of Mikados. These machines grouped under the class W were 55 locomotives of the subclass WA without a combustion chamber and 105 WB with ...
General
| Property | Northern Pacific classes WA, WB and W-1 WA/WB superheated |
|---|---|
| Built | 1912 |
| Manufacturers | Northern Pacific |
| Wheel arrangement | 2-8-2 (Mikado) |
| Gauge | 1,435 mm (Standard gauge) |
Dimensions and weights
| Property | Northern Pacific classes WA, WB and W-1 WA/WB superheated |
|---|---|
| Wheelbase | 10.59 m |
| Rigid wheelbase | 5.03 m |
| Service weight | 119.5 t |
| Adhesive weight | 93.4 t |
| Axle load | 26.6 t |
| Total weight | 206.5 t |
| Water capacity | 37,854 l |
| Fuel capacity | 17.2 t (coal) |
Boiler
| Property | Northern Pacific classes WA, WB and W-1 WA/WB superheated |
|---|---|
| Grate area | 4.041 m² |
| Firebox surface | 23.226 m² |
| Tube heating surface | 242.57 m² |
| Evaporative heating surface | 265.796 m² |
| Superheater surface | 52.955 m² |
| Total heating surface | 318.8 m² |
Power plant
| Property | Northern Pacific classes WA, WB and W-1 WA/WB superheated |
|---|---|
| Driver diameter | 1,600 mm |
| Boiler pressure | 13.8 bar |
| Expansion type | simple expansion |
| Cylinders | two, 610 x 762 mm |
Power
| Property | Northern Pacific classes WA, WB and W-1 WA/WB superheated |
|---|---|
| Power source | steam |
| Estimated power | 1,305 kW (1,774 PS) |
| Starting effort | 207.4 kN |
Calculated values
| Property | Northern Pacific classes WA, WB and W-1 WA/WB superheated |
|---|---|
| Factor of adhesion | 1 : 4.42 |
| Optimal speed | 39 km/h |
| Power-to-weight ratio | 10.9 kW/t |
| Heating Surface Equivalent | 487.8 m² |
| Cylinder volume/HSE | 1 : 911.78 |
| Adhesive weight/Total | 1 : 1.28 |
| Tractive force/Heating surface | 1 : 13.59 |
| Grate area/Heating surface | 1 : 78.88 |
| Firebox/Tube surface | 1 : 10.44 |
| Total/Superheater | 1 : 5.02 |
