Mumbai's Suburban Rail Network Eyes Underground Corridors to Ease Overcrowding
Mumbai's suburban rail network, a critical lifeline for millions of commuters, may be poised for a transformative structural overhaul. Western Railway (WR) and Central Railway (CR) are planning comprehensive feasibility studies for developing underground corridors along the heavily congested Churchgate-Virar and CSMT–Kalyan stretches. This ambitious initiative aims to tackle the persistent challenges of overcrowding and capacity limitations that plague the existing surface network.
Feasibility Studies in the Pipeline
Western Railway has already sought formal approval from the railway board to undertake a detailed study for its proposed underground corridor. Central Railway is expected to follow suit shortly for the CSMT–Kalyan section. The push to explore underground solutions is driven by multiple constraints that have made surface expansion increasingly untenable. Senior railway officials cite high land acquisition costs, dense urban development, and protracted litigation as major hurdles that delay project execution and inflate budgets.
"We are reaching a saturation point on surface expansion. Underground corridors offer a way to add capacity without the usual bottlenecks of land and encroachments," a senior railway official emphasized. While capital-intensive, underground corridors can bypass these obstacles while creating parallel capacity. They would also enable segregation of suburban services from goods and long-distance trains, potentially improving punctuality and paving the way for a modern, fully air-conditioned suburban system.
Learning from Metro Success
The railways are drawing confidence from the successful execution of underground infrastructure projects in Mumbai, particularly the Metro corridors such as the Aqua Line. These projects have demonstrated the city's technical capability to undertake complex tunnelling works in dense urban conditions. "The success of underground Metro corridors has shown that such engineering challenges can be managed efficiently. That experience is encouraging us to explore similar solutions for suburban rail," the official added.
Another key objective is to drastically reduce the "super-dense crush load"—a term describing extreme overcrowding in Mumbai's local trains. Globally, a density of five standing passengers per square metre is considered a crush load. In Mumbai's suburban trains, the benchmark is higher at around six persons per square metre. During peak hours, however, the system routinely experiences super-dense crush load conditions, with as many as 16 passengers standing within the same space, many carrying bags on shoulders or in hand.
Addressing Technical Failures and Congestion
Officials also highlighted that frequent technical failures on the existing network exacerbate congestion. "Any disruption—whether due to signalling glitches, overhead equipment (OHE) failures, track issues, or trespassing—has a cascading effect on the entire corridor, leading to bunching of trains and severe delays," an official explained. An underground system, with better access control and dedicated infrastructure, is expected to minimize such disruptions and enhance reliability.
By adding a new layer of capacity beneath existing corridors, authorities aim to ease pressure on the current network without disrupting services. This approach mirrors systems in global cities like London and Tokyo, where multi-level rail networks efficiently handle high commuter volumes. In Mumbai, underground metro corridors cost approximately Rs 1,100 crore per km—nearly 3–4 times higher than elevated lines at Rs 250–300 crore per km.
Current Operations and Proposed Alignments
Western Railway currently operates suburban services between Churchgate and Dahanu over a 120-km stretch, running around 1,414 services daily. The Churchgate–Virar section, approximately 60 km long, carries close to 30 lakh passengers daily, down from about 35 lakh before the pandemic. The proposed underground alignment is expected to run parallel to this existing corridor.
On Central Railway, suburban services run between Chhatrapati Shivaji Maharaj Terminus (CSMT) and Karjat/Kasara, with around 814 services catering to nearly 38 lakh passengers daily, reduced from 45 lakh pre-Covid. The CSMT–Kalyan stretch, spanning about 54 km, continues to face capacity constraints despite multiple track additions.
At present, WR has four lines between Churchgate and Marine Lines and between Borivli and Virar, while fifth and sixth lines operate between Mumbai Central and Borivli. The Mumbai Railway Vikas Corporation (MRVC) is extending additional lines between Borivli and Virar and adding third and fourth lines between Virar and Dahanu.
Similarly, on CR, four lines exist between CSMT and Kurla, with fifth and sixth lines under construction between Parel and Kurla. Beyond Parel, six lines are already operational up to Kalyan. Despite these expansions, demand continues to outpace capacity, underscoring the need for innovative solutions.
Parallel Initiatives and Future Decisions
In a parallel development, MRVC has commissioned a feasibility study for a 5-km underground stretch between Churchgate and Mumbai Central. MRVC managing director Vilas Wadekar stated, "We have commissioned a feasibility study to ascertain the financial and technical viability of an underground corridor between Churchgate and Mumbai Central. The final decision will be taken jointly by the ministry of railways and the state government."
Officials emphasized that the findings of these studies will be crucial in determining whether Mumbai's suburban railway can transition into a multi-tier network to meet future demand. As the city continues to grow, the success of these underground proposals could redefine urban mobility and alleviate the daily struggles of millions of commuters.
