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Union Pacific class 4000 “Big Boy”
After the success of the Challenger, the Union Pacific planned to have only one locomotive haul express freight trains on Wasatch Grade and Sherman Hill in the future. To haul trains of 3,600 short tons and over it wa...
General
| Property | Union Pacific class 4000 “Big Boy” Remove |
|---|---|
| Built | 1941 |
| Manufacturers | ALCO |
| Wheel arrangement | 4-8-8-4 (Big Boy) |
| Gauge | 1,435 mm (Standard gauge) |
Dimensions and weights
| Property | Union Pacific class 4000 “Big Boy” Remove |
|---|---|
| Length | 40.47 m |
| Wheelbase | 22.09 m |
| Rigid wheelbase | 5.56 m |
| Total wheelbase | 35.84 m |
| Service weight | 345.6 t |
| Adhesive weight | 244.9 t |
| Axle load | 30.8 t |
| Total weight | 539.5 t |
| Water capacity | 90,850 l |
| Fuel capacity | 25.4 t (coal) |
Boiler
| Property | Union Pacific class 4000 “Big Boy” Remove |
|---|---|
| Grate area | 13.963 m² |
| Firebox surface | 65.404 m² |
| Tube heating surface | 481.703 m² |
| Evaporative heating surface | 547.107 m² |
| Superheater surface | 229.099 m² |
| Total heating surface | 776.2 m² |
Power plant
| Property | Union Pacific class 4000 “Big Boy” Remove |
|---|---|
| Driver diameter | 1,727 mm |
| Boiler pressure | 20.7 bar |
| Expansion type | simple expansion |
| Cylinders | four, 603 x 813 mm |
Power
| Property | Union Pacific class 4000 “Big Boy” Remove |
|---|---|
| Power source | steam |
| Indicated power | 5,332 kW (7,250 PS) |
| Top speed | 113 km/h |
| Starting effort | 602.2 kN |
Calculated values
| Property | Union Pacific class 4000 “Big Boy” Remove |
|---|---|
| Factor of adhesion | 1 : 3.99 |
| Optimal speed | 55 km/h |
| Power-to-weight ratio | 15.4 kW/t |
| Heating Surface Equivalent | 1,332.3 m² |
| Cylinder volume/HSE | 1 : 697.46 |
| Adhesive weight/Total | 1 : 1.41 |
| Tractive force/Heating surface | 1 : 16.20 |
| Grate area/Heating surface | 1 : 55.59 |
| Firebox/Tube surface | 1 : 7.37 |
| Total/Superheater | 1 : 2.39 |
