The rail lines will enable rapid deployment of forces over the rugged, inhospitable and mostly snow-bound terrains. A high-level meeting of the government on July 14, chaired by the Deputy National Security Adviser Nehchal Sandhu and attended by representatives from ministries of defence and finance, identified four strategic lines that would be taken up on a priority as part of the BJP-led government’s budget announcement to build strategic railway lines, sources said.

The four lines have been prioritised from among the 14 strategic lines identified by the Ministry of Defence. China has high-speed railways connecting almost all areas of its side of the 3,448 km LAC.

This will be the first foray of India in the upper Himalayas to build strategic railway lines. This will enable rapid deployment of troops, especially the newly created Mountain Strike Corps mandated to face China. The railway line being built in Kashmir has a dual purpose - socio-economic and strategic. The other existing narrow gauge lines in Himachal Pradesh and Northern Bengal are of British vintage.

The most important railway lines will connect Leh in Jammu and Kashmir and Tawang in Arunachal Pradesh with the mainland India. Both these are on the LAC. The other two routes will connect one of the remotest parts of Arunachal Pradesh and facilitate easier military movement between other north-eastern states and Arunachal Pradesh.

The Tawang line is the most significant, considering the strategic importance of the area which is also a major Indian military base.

At present, there is no crossing over the Bhramaputra from Nagaland, Manipur and Mizoram forcing the troop movement by a circuitous road route.

For north India, the Rail link to Leh will be crucial. The pre-feasibility report pegs the cost of the entire 498-km all-weather broad gauge Bilaspur-Manali-Leh railway line at Rs 22,831 crore. The take off point could be either near Kiratpur Sahib in the foothills of Punjab or Pathankot.

A British era 181 km narrow gauge line exists between Pathankot and Joginder Nagar. It can be converted into board gauge. The conversion is expected to cost Rs 3,279 crore. The rail-line to Leh will pas through Upshi in Ladakh providing for further bifurcation to important conflict points at Demchok and Chumar in south-eastern Ladakh. From Upshi onwards, it's a flat plateau.

A sum of Rs 1,000 crore for this fiscal will be used in land acquisition and preparing detail project reports.