Wellington & Manawatu No. 17
New Zealand Railways class BC
No. 17 of the Wellington & Manawatu was the third Mikado tender locomotive ever built. Baldwin created it in 1901 and directly based it on the two Japanese Bt4/6 which had been the first Mikados and later became known as JGR class 9700. At the same time, Baldwin also built the NZR class Q Pacifics. Both had a similar design of trailing axle that carried a wide firebox. They were the biggest and most powerful locomotives of their time in New Zealand.
In contrast to the Q, No. 17 was a four-cylinder Vauclain compound with all cylinders on the outside, where the low pressure cylinders were above the high pressure ones. It was able to haul 280 tons over the challenging WMR main line with inclines of 1 in 56 or 1.8 percent. In 1908, when the WMR became part of the NZR, the locomotive became class BC No. 463. It was withdrawn in 1927, remaining the only Mikado in New Zealand.
Technical data
General
- Built
- 1901
- Manufacturers
- Baldwin
- Wheel arrangement
- 2-8-2 (Mikado)
- Gauge
- 1,067 mm (Cape gauge)
Dimensions and weights
- Length
- 16.94 m
- Wheelbase
- 7.37 m
- Total wheelbase
- 14.43 m
- Service mass
- 46.1 t
- Adhesion mass
- 34.4 t
- Total mass
- 72.5 t
- Rigid wheelbase
- 3.58 m
- Water capacity
- 7,548 l
- Fuel capacity
- 4.5 t (coal)
Boiler
- Grate area
- 2.323 m²
- Firebox surface
- 7.469 m²
- Tube heating surface
- 137.785 m²
- Evaporative heating surface
- 145.254 m²
- Total heating surface
- 145.3 m²
Power plant
- Driver diameter
- 1,092 mm
- Boiler pressure
- 13.8 bar
- Expansion type
- compound
- Cylinders
- four, HP: 292 x 508 mm and LP: 483 x 508 mm
Power
- Power source
- steam
- Estimated power
- 485 kW (659 PS)
- Starting effort
- 68.1 kN
- Starting effort simple
- 81.7 kN
Calculated values
- Factor of adhesion
- 1 : 4.96
- Optimal speed
- 43 km/h
- Power-to-weight ratio
- 10.5 kW/t
- Heating Surface Equivalent
- 182.6 m²
- Cylinder volume/HSE
- 1 : 881.76
- Adhesive weight/Total
- 1 : 1.34
- Tractive force/Heating surface
- 1 : 9.79
- Grate area/Heating surface
- 1 : 62.53
- Firebox/Tube surface
- 1 : 18.45