Indian Railway Tracks
The entire length of track used by Indian Railways stretches across the distance of 108,805 km and the total route length of the network extends up to 63,465 km. Approximately 40% of the total track kilometer is electrified. The ratings of the track section are done on the basis of speeds that range from 75 to 160 km/h.
Indian railways comprises of basically four types of gauges including the Broad gauge (Wider than the 1,435 mm), the Standard gauge, the meter gauge and two narrow gauge (762 mm and 610 mm). Broad gauge is the chief gauge utilized by the Indian railway and the Unigauge project is being carried out by railways which will convert all tracks to broad gauge subsequently.
Indian broad gauge measuring 1,676 mm has been the most widely used gauge in India that covers 89,771 km of track.
The meter gauge measuring 1,000 mm is common in some regions with less traffic. The Narrow gauges are laid on a small number of routes which lie in hilly terrains and in some private railways based on the consideration of the cost. These routes are complicated enough to convert them to broad gauge.
Narrow gauges extend the distance of about 3,350 km along the hill lines. It chiefly comprises of the Kalka-Shimla Railway, the Nilgiri Mountain Railway and the Darjeeling Himalayan Railway.
Based on the range of track temperature, Indian Railways categorizes the country into four zones. The greatest temperature variation takes place in the state of Rajasthan, where the disparity in temperature may surpass 70 °C.
Sleepers (ties) used are prepared of prestressed concrete at majority of the tracks. Apart from that steel or cast iron posts are also used. Few older lines use teak sleepers. Metal sleepers were also widely used prior to the arrival of concrete sleepers.