The Kolkata Metro or Calcutta Metro (Bengali: কলকাতা মেট্রো Kolkata Meṭro) is the underground rail network in Kolkata (Calcutta), India.

The Kolkata Metro or Calcutta Metro (Bengali: কলকাতা মেট্রো Kolkata Meṭro) is the underground rail network in Kolkata (Calcutta), India. It is considered to have the status of a zonal railway but is not a zone. It is run by the Indian Railways. It was the first underground built in India with service starting in 1984; the New Delhi Metro, which opened in 2002, is the second.

The line begins at Dum Dum in the north and continues south through Park Street, Esplanade in the heart of the city till the southern end in Tollygunge.

The burgeoning transport problem of Kolkata drew the attention of the city planners, the State Government and also the Government of India. It was soon realised that something had to be done and done quickly to cope with the situation. Bidhan Chandra Roy, at that time the Chief Minister of West Bengal, first conceived the idea in 1949 of building an Underground Railway for Kolkata to solve the problems to some extent. A survey was done by a team of French experts but nothing concrete came out. Efforts to solve the problem by augmenting the existing fleet of public transport vehicles barely touched the fringe of the problem as the roads account for only 4.2% of the surface area in Calcutta, compared to 25% in Delhi and even 30% in other cities.

With a view to finding an alternative solution, the Metropolitan Transport Project (Rlys)(i.e., Railways) was set up in 1969. After detailed studies, the MTP (Rlys) came to the conclusion that there was no other alternative but to construct a Mass Rapid Transit System. The MTP (Rlys) had prepared a Master Plan in 1971 envisaging construction of five rapid-transit lines for the city of Kolkata, totalling a route length of 97.5 km. Of these, the highest priority was given to the busy North-South axis between Dum Dum and Tollygunge over a length of 16.45 km, and the work on this project was sanctioned on June 1, 1972. The foundation stone of the project was laid by Smt. Indira Gandhi, the then Prime Minister of India, on December 29, 1972, and the construction work started in 1973.

At first, 5 lines were planned, but finally 3 selected. Those were -

Dum Dum - Tollygunge
Bidhannagar Sector 5 - Ramrajatala.
Dakshineshwar - Thakurpukur.
Since the commencement of construction, the project had to contend with several problems, such as the unavailability of sufficient funds till 1977-78, relocation of underground utilities, court injunctions, an irregular supply of vital materials, and so on. The laying of founding stone was done at 1972, but consturction of line 1 was actually started in 1978. It is 17 km. long with 17 stations (see above). Running of first metrocar on the line in 1984 was a great engineering challenge. The first section opened between Esplanade & Netaji Bhawan (then called Bhowanipore). There was no connections of this stretch with two depots - Dum Dum & Tollygunge. So metrocars were put down on the track near Esplanade by crane, directly digging the road surface. Initially, only four car trains were run until 1986. There were no magnetic gates or escalators or much entry gates at that time. Ordinary revolving gates allowed ordinary tickets. The metro service also served on only single line. Two years later, it extended upto Tollygunge, at the southern end. At that time, metro service started on double line. Magnetic tickets and more entry gates also introduced at that time. Metrocars also changed to eight car train.

In parallel, metro service also started from Dum Dum, at the northern end, to Belgachhia. But this short portion was not so popular and service closed later.

After 1986, many political incidents hampered the construction, and work almost stopped near six years. After restarting work, Dum Dum to Shyambazar metro service started in 1994. This portion was served by four car trains. Two months later, Esplanade - Chandni Chowk section opened, and Chandni Chowk - Central section opened three months later. The through service from Dum Dum to Tollygunge started in 1995, except Mahatma Gandhi Road station, which opened in 1996. Within this time, more magnetic gates, escalators and entry gates were added.