5th and 6th lines on HDN corridors as sections run above line capacity

Indian Railways is preparing the next stage of capacity expansion, with planning underway for 5th and 6th lines on HDN corridors linking the four major metro cities — Delhi, Howrah, Mumbai and Chennai, as reported by Times of India.

Also, the intention is to enable more passenger and freight trains to run on these High Density Network (HDN) corridors.

High Density Network (HDN) corridors and current line capacity

The numbers in the High Density Network help explain why capacity is in focus. The 11,051-km HDN forms the backbone of railways, accounting for 16% of the total network while handling 41% of total rail traffic, as outlined in Indian Railways’ “High Density Network in Indian Railways” note (PDF). Separately, around 8,400 km — over 60% of the HDN network — operates at 100–150% more than the line capacity, shaping the push for network expansion to boost capacity.

The seven HDN corridors linking major metro cities

The seven High Density Network 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).

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In addition, these routes sit at the centre of the current review of doubling and multitracking on HDN routes, alongside assessment of where additional lines may be needed; The Indian Express explainer also describes the HDN framing and how it concentrates traffic on a relatively small share of the network.

Doubling, multitracking and 5th and 6th line requirement on HDN routes

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. Meanwhile, zones have been asked to draft proposals for their respective sections, using line capacity, traffic requirements and future planning as the basis.

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.” At the same time, the official said decisions will be taken considering traffic projections, economic modes to be connected and unconnected areas.

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