Indian Railways class ZB
India 1925 0 produced
Among the IRS standard locomotives, the class ZB was a 2-6-2 with an axle load of six tons for a gauge of two and a half feet (762 mm). Distinct features were the outside frames and the Belpaire firebox that was optimized for burning low-grade coal. The design was introduced in 1925 and larger numbers were built by different manufacturers until the fifties.
Two railways which operated large numbers were the Gaekwad's Baroda State Railway and the Bengal Nagpur Railway. The first photo shows No. 9 of the Dehri Rohtas Light Railway, one of eight which were built by Hudswell Clarke and Krauss-Maffei. The second photo shows No. 22 of the Bombay, Baroda & Central India Railway. It was designated class ZBC due to its Caprotti valve gear.
Technical data
General
- Built
- 1925-1952
- Manufacturers
- Hudswell, Clarke & Co., W.G. Bagnall, Krauss-Maffei
- Wheel arrangement
- 2-6-2 (Prairie)
- Gauge
- 762 mm (Two feet six inch)
Dimensions and weights
- Service mass
- 29.5 t
- Adhesion mass
- 18.3 t
- Axle load
- 6.1 t
Boiler
- Grate area
- 1.301 m²
- Evaporative heating surface
- 54.534 m²
- Superheater surface
- 11.613 m²
- Total heating surface
- 66.1 m²
Power plant
- Driver diameter
- 864 mm
- Boiler pressure
- 11 bar
- Expansion type
- simple expansion
- Cylinders
- two, 305 x 457 mm
Power
- Power source
- steam
- Estimated power
- 373 kW (507 PS)
- Starting effort
- 46.1 kN
Calculated values
- Factor of adhesion
- 1 : 3.89
- Optimal speed
- 50 km/h
- Power-to-weight ratio
- 12.7 kW/t
- Adhesive weight/Total
- 1 : 1.61
- Tractive force/Heating surface
- 1 : 14.56
- Grate area/Heating surface
- 1 : 50.84
- Total/Superheater
- 1 : 4.70
