Western Australian Government Railways class N
Rising passenger numbers due to the gold rush prompted the WAGR to order tank locomotives in the 1890s. These were used in suburban service around Perth and in the Kalgoorlie area. They had the wheel arrangement 4-4-4T for good running characteristics in both directions and weighed only 44 tons. The drivers measured four feet and the cylinders were 15.5 by 21 inches. Combined with a boiler pressure of 160 psi, this resulted in a starting tractive effort of 14,300 pounds.
The first five were built by Neilson & Co. in 1896. 15 more had followed from Nasmyth, Wilson & Co. and twelve from Robert Stephenson & Co. by 1901. The total number was increased to 42 in 1907 and 1908 when the Midland Railway Workshops rebuilt ten 2-8-0 class O which had been built by Neilson & Co. in 1896. The first ones were withdrawn in the forties when the Dm and Dd class tank locomotives were introduced. Others were replaced by ADH diesel multiple units. The last one was withdrawn in 1961 and today N201 is on display in the Western Australian Rail Transport Museum.
Technical data
General
- Built
- 1896-1901, 1907-1908
- Manufacturers
- Neilson & Co., Robert Stephenson & Co., Nasmyth, Wilson & Co., Midland Railway Workshops
- Wheel arrangement
- 4-4-4T (Reading)
- Gauge
- 1,067 mm (Cape gauge)
Dimensions and weights
- Length
- 11.05 m
- Service mass
- 44.7 t
- Water capacity
- 7,276 l
- Fuel capacity
- 3 t (coal)
Boiler
- Grate area
- 1.463 m²
- Firebox surface
- 8.64 m²
- Tube heating surface
- 71.907 m²
- Evaporative heating surface
- 80.547 m²
- Total heating surface
- 80.5 m²
Power plant
- Driver diameter
- 1,219 mm
- Boiler pressure
- 11 bar
- Expansion type
- simple expansion
- Cylinders
- two, 394 x 533 mm
Power
- Power source
- steam
- Estimated power
- 280 kW (381 PS)
- Starting effort
- 63.6 kN
Calculated values
- Optimal speed
- 27 km/h
- Power-to-weight ratio
- 6.3 kW/t
- Heating Surface Equivalent
- 123.7 m²
- Cylinder volume/HSE
- 1 : 1,049.47
- Tractive force/Heating surface
- 1 : 16.49
- Grate area/Heating surface
- 1 : 55.06
- Firebox/Tube surface
- 1 : 8.32