The Blue Line (Line 1), also known as North–South Metro, is a rapid transit metro line of the Kolkata Metro in Kolkata, West Bengal, India. It consists of 26 operational stations from Dakshineswar to Kavi Subhash, out of which 9 of the stations are elevated, 2 are at-grade and the remaining 15 are underground. With a total distance of , the line connects Dakshineswar and New Garia and uses broad gauge tracks. Presently Kavi Subhash is closed so the terminal is Shahid Khudiram. This line was the first underground railway to be built in India, with the first operations commencing in October 1984 and the full stretch that was initially planned being operational by February 1995. On 28 December 2010, Kolkata Metro became the 17th zone of the Indian Railways. Being the country's first, and a completely indigenous process, the construction of the Kolkata Metro Blue Line was more of a trial-and-error affair, in contrast to the Delhi Metro, which has seen the involvement of numerous international consultants. As a result, it took nearly 23 years to completely construct around underground railway from Birpara up to Tollygunge.

It connects Green Line at Esplanade and Orange at Kavi Subhash, and will eventually connect Purple Line at Esplanade and Park Street, Yellow Line at Noapara and Pink Line at Baranagar.

Future Extensions Public transport experts have suggested that the line be extended from Dakshineswar to Bally (where it can connect with Howrah Division of Kolkata Suburban Railway) and eventually to Dankuni, an emerging industrial hub of Kolkata metropolitan region.

History

The laying of the founding stone was done in 1972, but actual construction of Blue Line started only in 1978. Blue Line is long with 26 stations (see above). Running of the first metro car on the line by 1984 was considered a great engineering challenge. Former railways minister A. B. A. Ghani Khan Chowdhury took a massive effort to perform it. The first section opened between Esplanade & Bhawanipore (now called Netaji Bhawan). First day Metro Railway Kolkata was started by Sri Tapan Kumar Nath and Sri Sanjay Sil. There were no connections of this stretch with the two depots at Dum Dum & Tollygunge (Now called Mahanayak Uttam Kumar). So metro cars had to be put down on the track near Esplanade by crane, by directly digging the road surface. Initially, only four-car trains were run until 1986. There were no magnetic gates or escalators at that time and ordinary revolving gates served as exits. The Metro too operated on only a single line. Two years later, Blue Line extended up to Tollygunge, at the southern end. At the same time, the metro service was extended to the double line. Magnetic tickets and more entry gates were also introduced at that time. The number of compartments in each train was increased to eight.

Metro service was also started from Dum Dum, at the northern end, to Belgachia in parallel with the extension of the line to the south. But this short portion was not popular and the service was closed down to be restarted when the entire stretch along the north–south corridor was completed.

After 1986 many political incidents hampered the construction, and work almost stopped for nearly six years. After restarting work, the Dum Dum to Shyambazar metro service was started in 1994. This portion was served by four-car trains. Two months later, the Esplanade – Chandni Chowk section was opened and Chandni Chowk – Central section opened three months later. The service from Dum Dum to Tollygunge started in 1995, with Mahatma Gandhi Road metro station, opening in 1996. During this time, more magnetic gates and escalators were added and the revolving gates were slowly phased out.

In 2009, a large number of stations on Blue Line were renamed by then Minister of Railways Mamata Banerjee.

On 22 February 2021, the Noapara – Dakshineswar stretch was inaugurated by Prime Minister Narendra Modi.

On 21 July 2024, the entire stretch from Dakshineswar to Kavi Subhash, crossed 1.92 lakh passenger mark for the first time on a single day.

On 28 July 2025, cracks were detected in the last four columns of the Line-1 Up platform at Kavi Subhash station, the line's southern terminus. So, the Line-1 platforms of the station were closed to passengers as a safety measure and the trains are being terminated at Shahid Khudiram station. However, the empty rakes would continue to run up to the station for reversal and maintenance at its depot.On investigation, it was found that the damage on the columns supporting the platforms were weakened beyond repair. So, Metro Authorities decided to raze the entire Line-1 complex of the station (keeping the tracks intact) and rebuild it. E-tenders were floated and the work is expected to be completed within ten months.

Timeline The following dates represent the dates the section opened to the public, not the private inauguration. HistoryExtension dateTerminalsLength 24 October 1984EsplanadeBhowanipore 12 November 1984Dum DumBelgachhia 29 April 1986Bhowanipur (now Netaji Bhavan)Tollygunge (now Mahanayak Uttam Kumar) 13 August 1994BelgachhiaShyambazar 2 October 1994EsplanadeChandni Chowk 19 February 1995ShyambazarGirish Park 19 February 1995Chandni ChowkCentral 27 September 1995CentralGirish Park 22 August 2009Tollygunge (Mahanayak Uttam Kumar)Garia Bazar (now Kavi Nazrul) 7 October 2010Garia Bazar (now Kavi Nazrul)New Garia (now Kavi Subhash) 10 July 2013Dum DumNoapara22 February 2021NoaparaDakshineswarTotal DakshineswarNew Garia (now Kavi Subhash)

Stations

The stations of this Line are: The stations of this Line are: Blue Line #Station NameDistance (km)OpeningConnectionsLayoutPlatform TypeEnglishBengali1Dakshineswarদক্ষিণেশ্বর022 February 2021 Dakshineswar Ma Bhabotarini Jetty GhatElevatedSide2Baranagarবরাহ নগর1.759 (Proposed) Baranagar Road3Noaparaনোয়াপাড়া2.3810 July 2013Side & Island4Dum Dumদমদম2.09112 November 1984 Dum Dum JnSide5Belgachiaবেলগাছিয়া2.151UndergroundIsland6Shyambazarশ্যামবাজার1.62515 February 19957Shobhabazar Sutanutiশোভাবাজার সুতানুটি0.9298Girish Parkগিরিশ পার্ক1.0019Mahatma Gandhi Roadমহাত্মা গান্ধী রোড0.76627 September 199510Centralসেন্ট্রাল1.03715 February 199511Chandni Chowkচাঁদনি চক0.59812Esplanadeএসপ্ল্যানেড0.70524 October 1984 (Under Construction)13Park Streetপার্ক স্ট্রীট0.808 (Under Construction)Side14Maidanময়দান1.536Island15Rabindra Sadanরবীন্দ্র সদন1.01516Netaji Bhavanনেতাজি ভবন0.84817Jatin Das Parkযতীন দাস পার্ক1.03329 April 198618Kalighatকালীঘাট0.62119Rabindra Sarobarরবীন্দ্র সরোবর1.864 Tollygunge20Mahanayak Uttam Kumarমহানায়ক উত্তম কুমার1.344 (Proposed)At GradeSide & Island21Netajiনেতাজি1.81422 August 2009ElevatedSide22Masterda Surya Senমাস্টারদা সূর্য সেন1.72223Gitanjaliগীতাঞ্জলি1.05324Kavi Nazrulকবি নজরুল1.24525Shahid Khudiramশহিদ ক্ষুদিরাম1.2757 October 201026Kavi Subhash (Under Construction; Trains terminate at Shahid Khudiram temporarily)কবি সুভাষ0.91 New GariaAt Grade

Alignment & interchanges Dakshineswar, Baranagar, Dum Dum, Noapara, Park Street, Mahanayak Uttam Kumar, Netaji, Masterda Surya Sen, Gitanjali, Kavi Nazrul, Shahid Khudiram and Kavi Subhash have side platforms; all other stations have island platforms. Mahanayak Uttam Kumar is an exception as it has both platforms on the sides as well as in the centre. Dakshineswar, Baranagar, Dum Dum, Rabindra Sarobar & Kavi Subhash have connections to interchange with Kolkata Suburban Railway. Shyambazar, Mahatma Gandhi Road, Esplanade, Kalighat. The EM Bypass can be accessed from the Shahid Khudiram metro station and Kavi Subhash metro station.

Extension up to New Garia (2010) Mamata Banerjee during her first tenure as the railway minister initiated the project of Tollygunge – Garia metro extension. During her second tenure (2009–2011) she inaugurated the extension, and also introduced new Air Conditioned rakes, manufactured indigenously at the Integral Coach Factory.

The new extension to Garia Bazar in the south opened to the public on 23 August 2009. The Garia Bazar station was named after Kavi Nazrul. A final extension, in the southern end, from Kavi Nazrul (Garia Bazar) to Kavi Subhash (New Garia) was inaugurated on 7 October 2010, bringing the total number of stations to 23. On the same day, two Air-Conditioned rakes were also pressed into service.

Extension up to Noapara (2013) and Dakshineswar (2021) The line was extended up to Noapara from Dum Dum on 10 July 2013. The line was further extended from Noapara to Dakshineswar (4.1 km) is now complete & operational. It will be met by a metro line from Barrackpore at Baranagar (12.5 km). Trial runs for this stretch started on 23 December 2020, after delay due to COVID-19 pandemic. The stretch was inaugurated on 22 February 2021 & commercial operations began from the following day.

The stations on this stretch are :

Noapara Baranagar Dakshineswar

Features

Technical features

Metro construction is of a very complex nature requiring the application of several new technologies in the fields of civil, electrical, signaling and telecommunication engineering. Indian engineers backed by their own experience and supplemented by their studies abroad adopted advanced technologies in the following fields for the first time in India.

Cut and cover method of construction using diaphragm walls and sheet piles. Use of extensive decking to keep the traffic flowing over the cut while construction is in progress underneath. Shield tunneling using compressed air and airlocks. Ballastless track using elastic fastenings, rubber pads, epoxy mortar and nylon inserts. Air-conditioning and ventilation system for environmental control of stations and tunnels. Third Rail current collection system for traction. Underground substations with dry-type transformers and SF6 circuit breakers. Tunnel-Train VHF-radio communication system. Microprocessor-based train control and supervisory remote control system for substations. Automatic ticket vending and checking system.

Salient features Total route length Stations 26 (15 underground, 2 on the surface and 9 elevated) Gauge , Indian Broad Gauge Cars per train 8 Maximum permissible speed Average speed Voltage 750 V D.C. Method of current collection Third Rail Travel Time: Dakshineswar to Kavi Subhash 62 minutes (approx.)Headways Average 10 minutes Total estimated cost of the project (approx.) Environment control Air conditioners are used in all trains.

Proposed Feature and Expansion Platform Screen Doors (PSDs) are a system of full height/half height motorized sliding doors that provide controlled access to the trains and protect the platform edge. PSD work is proposed for all stations in this line to minimize accidents common in this route. This plan was proposed after the successful utilization of Platform Screen Doors to keep the number of suicidal cases on the Green Line to absolute zero.

Metro Railway also plans to extend the platform and viaduct of Dakshineswar metro station by ~ via erection of two new pillars beyond the current length to facilitate a crossover so that the trains can switch tracks faster in order to increase the frequency of services to the Noapara–Dakshineswar stretch.

Rolling stock

ICF/BHEL

ICF/MEDHA

CRRC Dalian