Indian locomotive class WP

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WP is the name of the class of a steam locomotive used in India. It was a Pacific class introduced after World War II for passenger duties, marking the change from 'X' to 'W' for broad gauge locos. It was capable of doing up to 110km/h and was easily recognized by the cone-shaped bulging nose with (usually) a silver star device painted on it. WP's were designed specifically for low-calorie, high-ash Indian coal, by Railway Board designers in India.

755 WPs were built between 1947 and 1967, bearing serial numbers 7000 to 7754. The first batch of sixteen came from Baldwin, USA in 1947, and these were classed WP/P. (P for Prototype). Some of the later WP were built as WP/1. The WP/1s were 5 tonnes heavier. Production began on Indian ground in 1961 at Chittaranjan Locomotive Works.

It is mistakenly believed that the bullet nose makes it streamlined and thus helps reduce air resistance. This is completely wrong as anyone who has studied fluid mechanics will know that a hemispherical smokebox door, i.e., the WP's famous bullet-nose, cannot be the cause of low aerodynamic drag or streamlining.

Several WP's remained in service until the '80s. Early prototypes from Baldwin were labelled WP/P; CLW versions after about 1965 were labelled WP/1. A few reconditioned WP's have been exported to countries in the middle East (after regauging?).

WP was Indian railways' crack locomotive in 60's and 70's. Before the advent of diesel and electric locomotives several prestigious trains, such as the Taj Express, the Grand Trunk Express, Howrah-Madras Mail, Frontier Mail and the AirConditioned Express were once hauled by WP class locomotives.

1 Technical specifications
2 Notes and references
3 See also
4 External links

[edit] Technical specifications

Wheel arrangement:4-6-2, Tractive effort: 30,600lb, Axle load: 18.5 tons, Boiler: 5'11", Boiler Pressure: 210 psig, Heating Surface: 3082 sq.ft, Grate Area: 46 sq.ft, Cylinders: (2), 20 1/4" Bore x 28" Stroke, Wheel Diameter: 5'-7", Nominal Axle Load: 18.1 tonnes, Maximum Train Load: 680 tonnes, Drawbar Horsepower:1500 hp (est.)