Kolkata Metro

The Kolkata Metro is a rapid transit system serving the city of Kolkata and the Kolkata Metropolitan Region in West Bengal, India. Opened in 1984, it is the first and oldest operational rapid transit system in India. It has 5 color-coded lines with 58 operational stations with a total length of 73.42 km (45.62 mi), making it India's fourth largest and fourth busiest metro rail system. The system has a mix of underground, at-grade, and elevated stations using both broad-gauge and standard-gauge tracks. It operates on a 750 V DC Third rail system. Trains operate between 06:30 and 22:44 IST.

The Kolkata Metro was initially planned in the 1920s, but construction started in the 1970s. The first underground stretch, from Bhawanipore (now Netaji Bhawan) to Esplanade, opened in 1984. A truncated section of Green Line, or the East–West Corridor, from Salt Lake Sector V to Howrah Maidan, was opened in 2020. Purple Line, or the Joka–Eden Gardens Corridor (currently truncated in Majerhat), opened in 2022, Orange Line, from Kavi Subhash to Beleghata, opened in 2024. The Yellow Line, from Noapara to Jai Hind, opened in 2025.

As of 2025, Kolkata metro has the deepest metro station and largest underground metro station in India. Howrah metro station of Green Line is the deepest metro station in India with depth of 34 m (112 ft). Also at the time of inauguration, it was the largest metro station of India. In August 2025, Jai Hind metro station of Yellow Line became the largest metro station in India, as well as one of largest in Asia.

Metro Railway, Kolkata and Kolkata Metro Rail Corporation are the owners and operator of the system. On 29 December 2010, Metro Railway, Kolkata, became the 17th zone of the Indian Railways, completely owned and funded by the Ministry of Railways. It is the only metro system in the country to be controlled entirely by Indian Railways. Around 300 daily train trips carry more than 800,000 passengers.

In the September 1919 session of the Imperial Legislative Council at Shimla, a committee was set up by W. E. Crum that recommended a metro line for Kolkata (formerly Calcutta). This line was supposed to connect Bagmari in the east to Benaras Road, Salkia, in Howrah in the west via a tunnel beneath Hooghly River. The estimated construction costs were £3,526,154, about ₹36.4 crore (equivalent to ₹70 billion or US$830 million in 2023) based on current exchange rates, and the proposed deadline was 1925–1926. The proposed line was 10.4 km (6.5 mi) long, about 4 km (2.5 mi) shorter than the current Green Line, which would connect East Bengal Railway in Bagmari and East Indian Railway in Benaras Road. The tickets were priced at 3 annas (₹ 0.1875) for the full trip. Crum also mentioned a north–south corridor back then. An east–west metro railway connection, named the "East–West Tube Railway", was proposed for Kolkata in 1921 by Harley Dalrymple-Hay. All the reports can be found in his 1921 book Calcutta Tube Railways. However, in 1923, the proposal was not undertaken due to a lack of funds.

Then the Chief Minister of West Bengal, Bidhan Chandra Roy, reconceived the idea of an underground railway for Kolkata from 1949 to 1950. A team of French experts conducted a survey, but nothing concrete materialized. Efforts to solve the traffic problem by augmenting the existing fleet of public transport vehicles hardly helped, since roads accounted for only 4.2 percent of the surface area in Kolkata, compared with 25 percent in Delhi and 30 percent in other cities. To find alternative solutions, the Metropolitan Transport Project (MTP) was set up in 1969. The MTP, with the help of Soviet specialists, Lenmetroproekt and East German engineers, prepared a master plan to provide five rapid-transit (metro) lines for the city of Kolkata, totaling a length of 97.5 km (60.6 mi), in 1971. Three were selected for construction. These were:

The highest priority was given to the busy north–south corridor between Dum Dum and Tollygunge over a length of 16.45 km (10.22 mi); work on this project was approved on 1 June 1972. A tentative deadline was fixed to complete all the corridors by 1991.

Since it was India's first metro and was constructed as a completely indigenous process, a traditional cut-and-cover method and driven shield tunneling was chosen and the Kolkata Metro was more of a trial-and-error affair, in contrast to the Delhi Metro, which saw the involvement of multiple international consultants. As a result, it took nearly 23 years to completely construct the 17 km (11 mi) underground railway.