Question

Explain the necessity of gradients. Discuss all types of gradients giving their permissible values adopted on Indian Railways.

Answer 1

Gradient

Gradient is rate of change of elevation or vertical distance along the longitudinal direction. It may be ascending or descending slope which depends on the situation.

Necessity of Gradient

• Gradient is necessary to connect stations at different elevation.
• Gradient helps in drainage of water in the railway tracks and stations.
• For smooth operating of vehicle on abrupt change of contours, gradient is provided.
• It minimises the cost of earthwork and refiling. Providing gradient with permissible limits is better than making the site plain in mountaneous areas.

Types of Gradients

• Ruling Gradient
• Pusher Gradient
• Momentum Gradient
• Station Yard Gradient

Ruling Gradient

Ruling Gradient is the maximum permissible gradient provided in a railway track with regard to hauling capacity of the engines. In Indian railways, the following permissible ruling gradient are adopted

Plains	1 in 150 to 1 in 200
Hilly Regions	1 in 100 to 1 in 150

Pusher Gradient

The rising gradient which is steeper tha ruling gradient and along which trains climb only with the help of additional locomotives is called as Pusher Gradient. 1in 37 is the steepest pusher gradient provided in Ghat section between Bombay and Pune.

Momentum Gradient

The rising gradient is followed by a falling gradient and along which trains climb more easily due to momentum acquired by them over the falling gardient is called momentum gradient. It may be provided steeper than ruling gardient.

Station Yard Gradient

Station Yard Gradient is the minimum gradient provided on station yards for drainage.

Permissible values of Station Yard Gradient

Maximum gradient in yard	1 in 400
Minimum gradient in yard	1 in 1000