Norfolk & Western class A
The Norfolk & Western class A consisted of a total of 43 simple articulated locomotives, which were suitable for different types of trains from slow coal trains to passenger trains. The trailing bogie allowed for a very large firebox, generating around 5,400 horsepower even without thermic syphons or water tubes. To reduce friction, roller bearings were installed on all axles, the last five even had roller bearings on the connecting and coupling rods.
The maximum load for slow freight trains on flatter lines was between 13,000 and 14,500 short tons. They could haul express freight trains up to 5,200 short tons and with passenger trains they could reach speeds of 70 mph and more. Because of the large water usage, old tenders were converted to water-only tenders, adding an additional 20,800 gallons to the 22,000 gallon capacity of the regular tender. With a tender and an additional water car, the locomotives weighed 1,233,000 pounds. Their service life ended between 1958 and 1959.
Today number 1218 built in 1943 still exists, which was restored between 1985 and 1987. It was then the world's strongest pulling operational steam locomotive. With the termination of the Norfolk & Western steam program, however, it was stored again after only four years. Now it is waiting to be refurbished again, although this is rather unlikely to happen.
Technical data
General
- Built
- 1936-1950
- Manufacturers
- Roanoke
- Wheel arrangement
- 2-6-6-4
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Length
- 37.12 m
- Wheelbase
- 18.40 m
- Total wheelbase
- 33.00 m
- Service mass
- 259.9 t
- Adhesion mass
- 196.1 t
- Total mass
- 431.6 t
- Rigid wheelbase
- 7.52 m
- Axle load
- 32.7 t
- Water capacity
- 83,279 l
- Fuel capacity
- 29.9 t (coal)
Boiler
- Grate area
- 11.334 m²
- Firebox surface
- 54.534 m²
- Tube heating surface
- 616.784 m²
- Evaporative heating surface
- 671.318 m²
- Superheater surface
- 251.117 m²
- Total heating surface
- 922.4 m²
Power plant
- Driver diameter
- 1,778 mm
- Boiler pressure
- 20.7 bar
- Expansion type
- simple expansion
- Cylinders
- four, 610 x 762 mm
Power
- Power source
- steam
- Estimated power
- 4,623 kW (6,286 PS)
- Top speed
- 113 km/h
- Starting effort
- 560.0 kN
Calculated values
- Factor of adhesion
- 1 : 3.44
- Optimal speed
- 50 km/h
- Power-to-weight ratio
- 17.8 kW/t
- Heating Surface Equivalent
- 1,446.2 m²
- Cylinder volume/HSE
- 1 : 615.12
- Adhesive weight/Total
- 1 : 1.33
- Tractive force/Heating surface
- 1 : 12.68
- Grate area/Heating surface
- 1 : 81.39
- Firebox/Tube surface
- 1 : 11.31
- Total/Superheater
- 1 : 2.67