NEW DELHI: For the next phase of network expansion, the railway ministry has started preparation for laying 5th and 6th lines on the High Density Network (HDN) corridors connecting the four major metro cities — Delhi, Howrah, Mumbai and Chennai — so that more passenger and freight trains can run on these corridors.This is significant considering that the 11,051-km HDN forms the backbone of railways, accounting for 16% of the total network, but handling 41% of total rail traffic. Around 8,400-km of this, over 60% of the HDN network operate at 100-150% more than the line capacity.The seven HDN corridors are – Delhi–Howrah (1,422 km), Howrah–Mumbai (2,039 km), Delhi–Mumbai (1,321 km), Delhi–Guwahati (1,875 km), Delhi–Chennai (2,041 km), Howrah–Chennai (1,117 km) and Mumbai–Chennai (1,238 km).TOI has learnt that recently the railway board called a meeting of senior officials from all zones to finalise the planning of doubling, multitracking and 5th and 6th line requirement on HDN routes. The zones have been asked to prepare proposals for their respective sections based on line capacity, traffic requirements and future planning.Responding to questions on the proposed augmentation plan, a senior railway official said, “Based on traffic projections, 5th and 6th lines may be required in some of the HDN corridors. Railways is examining this. This will be based on traffic study, which is yet to be carried out.”On the criteria for finalising the plan, the official said the decisions for laying 5th and 6th lines will be taken considering traffic projections, economic modes to be connected and unconnected areas.
