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Northern Pacific classes Z-6 to Z-8
The first Challenger locomotives, i.e. the wheel arrangement 4-6-6-4, were built in 1936. In addition to the well-known Challenger of the Union Pacific, this was the Z-6 class of the Northern Pacific. Since these had ...
General
| Property | Northern Pacific classes Z-6 to Z-8 Remove |
|---|---|
| Built | 1936-1937 |
| Manufacturers | ALCO |
| Wheel arrangement | 4-6-6-4 (Challenger) |
| Gauge | 1,435 mm (Standard gauge) |
Dimensions and weights
| Property | Northern Pacific classes Z-6 to Z-8 Remove |
|---|---|
| Wheelbase | 18.85 m |
| Rigid wheelbase | 7.42 m |
| Service weight | 284.2 t |
| Adhesive weight | 197.3 t |
| Axle load | 33 t |
| Total weight | 464.9 t |
| Water capacity | 83,279 l |
| Fuel capacity | 24.5 t (coal) |
Boiler
| Property | Northern Pacific classes Z-6 to Z-8 Remove |
|---|---|
| Grate area | 14.149 m² |
| Firebox surface | 77.946 m² |
| Tube heating surface | 466.281 m² |
| Evaporative heating surface | 544.227 m² |
| Superheater surface | 196.397 m² |
| Total heating surface | 740.6 m² |
Power plant
| Property | Northern Pacific classes Z-6 to Z-8 Remove |
|---|---|
| Driver diameter | 1,753 mm |
| Boiler pressure | 17.2 bar |
| Expansion type | simple expansion |
| Cylinders | four, 584 x 813 mm |
Power
| Property | Northern Pacific classes Z-6 to Z-8 Remove |
|---|---|
| Power source | steam |
| Estimated power | 4,847 kW (6,590 PS) |
| Starting effort | 463.8 kN |
Calculated values
| Property | Northern Pacific classes Z-6 to Z-8 Remove |
|---|---|
| Factor of adhesion | 1 : 4.17 |
| Optimal speed | 64 km/h |
| Power-to-weight ratio | 17.1 kW/t |
| Heating Surface Equivalent | 1,326.8 m² |
| Cylinder volume/HSE | 1 : 656.85 |
| Adhesive weight/Total | 1 : 1.44 |
| Tractive force/Heating surface | 1 : 13.08 |
| Grate area/Heating surface | 1 : 52.34 |
| Firebox/Tube surface | 1 : 5.98 |
| Total/Superheater | 1 : 2.77 |
