Kolkata Metro, which began operations in 1984 as India’s first Metro railway system, has expanded into a substantial urban transport network serving the city. The Ministry of Railways has announced plans to modernise the system with 60 new-generation train sets over the next four to five years, marking a significant step in upgrading the network’s capacity and technology.
Key facts
- Current network: 73.42 km across five colour-coded lines with 58 stations
- Original line: 3.4 km between Esplanade and Netaji Bhavan, opened 24 October 1984
- Passenger traffic in 2025-26: 23.60 crore passengers annually
- Expansion between 2014 and 2025: 45 km of new track commissioned
- Prior expansion (1972 to 2014): 28 km commissioned over 42 years
- New trains: 60 new-generation Metro rakes to be inducted over four to five years
- Projected future network: approximately 130 km
- Under-river tunnel: 520 metres beneath Hooghly River, constructed in 66 days
From modest start to multi-corridor network
The Kolkata Metro project began in 1972, but commercial service only commenced on 24 October 1984 with a single 3.4-km corridor connecting Esplanade to Netaji Bhavan (formerly Bhowanipore) with three intermediate stations. This modest beginning marked India’s entry into Metro rail transport. Over the next three decades, the network remained relatively small, with only 28 km added between the project’s launch and 2014. The pace of expansion accelerated significantly after 2014, with 45 km of track commissioned in just 11 years, demonstrating a marked shift in project execution speed and investment priority.
Current network structure
Today, Kolkata Metro operates five colour-coded lines serving different parts of the city. The Blue Line includes a 28-km stretch from Kavi Subash to Noapara, plus a 4.14-km extension to Dakshineswar. The Yellow Line comprises the 6.77-km Noapara to Jai Hind Bimanbandar section, which directly connects commuters to Netaji Subhas Chandra Bose International Airport. The Purple Line runs 14 km from Joka to Esplanade, though currently only the 7.74-km Joka-Majerhat portion is operational; the remaining 6.26 km between Majerhat and Esplanade remains under construction. The Orange Line includes the 9.8-km New Garia to Belaghata section. The Green Line, spanning 16.55 km from Howrah Maidan to Salt Lake Sector V, was commissioned in stages and represents a major engineering accomplishment.
Engineering milestone: under-river tunnel
A defining achievement of Kolkata Metro is the Green Line’s crossing beneath the Hooghul River. The twin subaqueous tunnels were constructed using Earth Pressure Balancing Tunnel Boring Machines through clayey silt, a challenging geological formation. The underwater portion measures 520 metres and was completed in an exceptionally rapid 66 days. These tunnels run approximately 350 metres downstream of the iconic Rabindra Setu (Howrah Bridge) and represent India’s first Metro tunnel constructed beneath a river. Additionally, the Howrah Metro station reaches depths of approximately 30 metres, demonstrating the engineering complexity of the project.
Modernisation and passenger services
The Railways Ministry announced in June 2026 that 60 new-generation Metro train sets would be inducted into the Kolkata Metro fleet over the coming four to five years. This modernisation initiative aims to enhance the network’s capacity and service quality as passenger demand continues to grow. During 2025-26 alone, the Metro Railway transported 23.60 crore (236 million) passengers, underlining the system’s critical role in the city’s public transport infrastructure.
Digital transformation has accompanied the physical expansion. The Aamar Kolkata Metro mobile application allows passengers to purchase tickets online, including QR-based options, and facilitates digital payments. The platform also supports digital purchase of tokens, Smart Cards and Smart Card recharges, reducing reliance on traditional ticketing methods.
Future expansion plans
The Metro Railway projects the network will expand to approximately 130 km in coming years. Current projects focus on extending connectivity towards the airport, northern suburbs, southern Kolkata and central business districts, ensuring the Metro reaches a wider cross-section of the city’s residents and workplaces.
What this means for you
If you live in or commute within Kolkata, the Metro network continues to expand, bringing rapid transit closer to more residential and commercial areas. The introduction of 60 new trains will improve service frequency and reduce crowding during peak hours. The digital ticketing system makes it easier to purchase and manage tickets through your smartphone without visiting counters. The focus on airport connectivity benefits frequent travellers. For students and young professionals, the expanding network reduces commute times and travel costs, potentially making outer areas more accessible for residence and work.