Plans for a metro rail system for Chennai started in 2007–08 with construction commencing in February 2009. Test runs began in 2014, and the first segment of the metro between the Alandur and Koyambedu stations on the Green Line began operations on 29 June 2015. On 21 September 2016, operations on the Blue Line commenced between Chennai Airport and Little Mount. The underground stretch from AG-DMS to Washermanpet of the Blue Line opened on 10 February 2019, completing the first phase. Additionally, The Chennai Metro is the first metro system in India to operate an Inter-Corridor Line system.
As a part of the second phase, three more lines covering a length of 92.8km (57.7mi) are planned and are under construction. The Chennai Mass Rapid Transit System (MRTS), operated by the Indian Railways, is planned to be incorporated into the Chennai Metro. A light rail has been proposed to connect Tambaram on the Chennai suburban rail network with Velachery on the MRTS. Further extensions are also planned for the three lines under construction.
The Delhi Metro Rail Corporation was tasked to prepare a project report for the implementation of a metro rail system in Chennai. The Government of Tamil Nadu approved the first phase of the project in November 2007. The first phase was planned with two lines covering 45.1km (28.0mi) with 25km (16mi) being underground. The first corridor would connect Washermanpet with Chennai International Airport extending for 23.1km (14.4mi) with 14.3km (8.9mi) being underground and the second corridor would connect St.Thomas Mount with Chennai Central extending for 22km (14mi) with 9.7km (6.0mi) being underground. In December 2007, the Chennai Metro Rail Limited (CMRL) was established as a joint venture between the union and state governments to execute the project. The Planning commission gave an in-principle approval for the project in April 2008 with the final approval by the Union Council of Ministers in January 2009. The estimated base cost of the first phase was ₹146 billion (US$1.5billion) of which 59% was loaned by Japan International Cooperation Agency (JICA). The Government of India contributed 15% of the cost and the Government of Tamil Nadu financed the remaining 21% of the project.
Construction of an elevated section in the first phase in 2011Construction of Anna Nagar East underground station in 2015
Major contracts awarded during Phase 1 construction
In August 2012, a construction worker was killed and six others were seriously injured after a crane failed and crashed at an under construction site near Pachaiyappa's College and on 10 January 2013, a 22-year-old construction worker was killed and three others were injured at a construction site between Alandur and St. Thomas Mount. On 6 November 2013, a test run was conducted along a stretch of 1km (0.62mi) track. The project faced several delays and missed deadlines due to problems with land acquisition and cancellation of construction contracts. On 11 January 2014, a crane toppled over, killing a 20-year-old construction worker and seriously injuring another at Saidapet.
Chennai Metro during trials in early 2014
On 14 February 2014, the maiden trial run was conducted between Koyambedu and Ashok Nagar stations. The metro received the statutory speed certification clearance from the Research Design and Standards Organisation in August that year. In January 2015, a report was submitted to the Commissioner of Metro Rail Safety (CMRS) for mandatory safety approvals. After inspecting the infrastructure, the CMRS submitted the report to the Railway Board in April 2015.
Elevated track over the Adyar riverUnion minister Venkaiah Naidu along with the then Chief minister of Tamil Nadu Edappadi K. Palaniswami inaugurating Thirumangalam - Nehru Park stretch of Phase-I, in 2017
Operations on the Green Line between the Alandur and Koyambedu stations commenced on 29 June 2015. The Blue Line segment from the Airport and Little Mount stations commenced operations on 21 September 2016. The first underground section between Thirumangalam to Nehru Park on the Green Line opened on 14 May 2017, and the extension to Chennai central was completed on 25 May 2018 along with the section from the Saidapet and AG-DMS stations on the blue line. On 10 February 2019, the underground stretch from AG-DMS to Washermanpet of Blue Line was opened, marking the completion of the first phase of the metro.
Phase 1 Extension
In 2014, a 9km (5.6mi) northern extension of the Blue Line was announced by the Government of Tamil Nadu. The extension would run from Washermanpet to Wimco Nagar and consist of nine stations. Construction started in July 2016 with the first trial runs conducted in December 2020. The line opened for passenger traffic on 14 February 2021, increasing the length of the operational metro system to 54.1km (33.6mi). The expansion costed ₹37.7 billion (US$390million) of which 57% was loaned by JICA. In 2021, the CMRL proposed a further extension of the blue line to connect the airport with Kilambakkam at an estimated cost of ₹46.25 billion (US$480million), which is clubbed with Phase III in 2026.
In July 2016, the Government of Tamil Nadu announced that the second phase would have three lines spanning 104km (65mi) with 104 stations. Two corridors would extend from Madhavaram Milk Colony connecting with Siruseri SIPCOT and Sholinganallur respectively with the third corridor connecting Koyambedu with Lighthouse on the Marina beach. In July 2017, the state government announced an extension of Phase II, involving a section from Lighthouse up to Poonamallee Bypass with an intersection with the Madhavaram–Sholinganallur line at Alwarthirunagar. The second phase would span 118.9km (73.9mi) with 128 stations. The stations for the second phase were designed to be smaller than the stations of the first phase to reduce the cost and time of construction. In 2019, the Madras High Court questioned the state government on the construction method of the tunnels and its impact on the water bodies. The second phase was estimated to cost ₹63.25 billion (US$660million) of which ₹47.1 billion (US$490million) was loaned by JICA.
On 20 November 2020, foundation stone for the second phase was laid and construction commenced. On 14 February 2021, Prime Minister of India announced that the government has set aside ₹630 billion (US$6.5billion) for the construction of the second phase and its further extension. In May 2023, the CMRL announced minor changes to the lines' alignment and that nine stations would be scrapped in the revised plan. Hence, the total length of the second phase was reduced to 116.1km (72.1mi).
Construction of Madhavaram Milk Colony underground station as part of the Phase 2 in 2025Construction of elevated section of Purple line along OMR as a part of Phase 2 in 2024Prime Minister Narendra Modi along with Chief Minister of Tamil Nadu, Vijay inaugurating the Poonamallee-Vadapalani Stretch of Phase II of Chennai Metro Rail Project, on October 11, 2026.
Major contracts awarded during Phase 2 construction
As of May 2024[update], about 20km (12mi) of the second phase had been completed. In March 2025, the first trial run on the Phase II network was conducted on a 3km (1.9mi) stretch between Poonamallee and Mullaithottam on the proposed Yellow Line. In April 2025, trial runs began on a 10km (6.2mi) stretch between Poonamallee and Porur Junction stations on the same line. The RDSO conducted inspection on the same stretch in August 2025, and the Railway Board provided approval for the operation of signals on the line in December 2025. Following the conclusion of safety checks by the CMRS in February 2026, the operations on Poonamallee Bypass to Vadapalani stretch on the Yellow Line commenced on 11 October 2026., with no intermediate stoppages between Porur and Vadapalani,
In 2022, the state government proposed an extension plan spanning 93km (58mi) for the three under construction lines of the second phase. The proposal involved extension of Purple Line from Siruseri SIPCOT to Kilambakkam, Yellow Line from Poonamallee to Parandur and Red Line from Koyambedu to Avadi. The proposed extension of second phase lines from Siruseri to Kilambakkam, Poonamallee to Parandur, and Koyambedu to Avadi were projected to cost ₹54.58 billion (US$570million), ₹107.12 billion (US$1.1billion), and ₹67.36 billion (US$700million) respectively. Between late 2023 and early 2024, feasibility reports submitted by the CMRL suggested dropping the proposed extension of the purple line due to economic viability and going ahead with the planned extensions of the other two lines, spanning 59.7km (37.1mi). In May 2024, the state government proposed a new 16km (9.9mi) extension from Madhavaram to Ennore, which was later changed as Assisi Nagar to Wimco Nagar extension in 2026.
In May 2024, the Government of Tamil Nadu approved both the extensions of the Red Line from Koyambedu to Pattabiram and Yellow Line from Poonamallee to Parandur at an estimated cost of ₹99.28 billion (US$1.0billion) and ₹159.06 billion (US$1.7billion) respectively, forwarding to Government of India for final approval. In July 2026, Chennai Metro planned to club Airport - Kilambakkam extension of Phase-I as well as above planned extensions with proposed Phase III network, with few more stretches planned to link northern suburbs of city based on feasibility reports. Koyambedu metro station is set for upgrade with Phase III connectivity (Koyambedu - Pattabiram) with Phase I and Phase II stations of Green Line and Red Line respectively. CMRL also plans extending Airport to Kilambakkam extension further south, till Chengalpattu.
Chennai MRTS is proposed to be handed over to Chennai Metro
In 2017, the state government proposed to integrate the Chennai Mass Rapid Transit System (MRTS) into the Chennai Metro. In July 2018, PwC said that the merger would cost around ₹30 billion (US$310million) to convert the rolling stock and install other facilities for the merger. On 11 May 2022, Southern Railway of the Indian Railways granted an in-principle approval for the integration of the MRTS into the metro. As per the plan, the railway would handover the MRTS to the CMRL once the expansion of the MRTS is completed. However, the extended second phase of the MRTS project, connecting Velachery with St. Thomas Mount experienced delays, and was completed in March 2026. Once the takeover is completed, CMRL will upgrade the MRTS system including tracks, security, ticketing system and rolling stock.
In 2020, a light rail was proposed to connect Tambaram railway station of the existing suburban rail network with Velachery on the MRTS, as part of plans to link the different urban transit lines in the city. Feasibility studies for the project was commissioned in February 2023 by the Chennai Unified Metropolitan Transport Authority (CUMTA). In March 2024, a study was commissioned to re-assess the feasibility of establishing a new corridor connecting Tambaram with Velachery with an extension to connect with existing Guindy metro station. In 2025, the government decided to develop the stretch as a regular metro corridor.
Others
MetroS, the Chennai Metro headquarter building at Nandanam
The third phase of the Chennai Metro is under planning as a part of the Chennai Comprehensive Mobility Plan, with upgrades to existing Phase-I stations and procurement of 28 new six-coach metro trains. The CMRL is also involved in the feasibility studies for the development of metro rail transport in the cities of Coimbatore, Madurai and Tiruchirapalli.
CMRL developed the Kathipara Urban Square as a multi-modal transport hub with parking and recreational areas. In 2023, the CMRL proposed the development of Central Square around its headquarters with commercial complexes and multi-storied buildings. In April 2025, CMRL announced that it has identified public spaces in Adyar and Velachery which can be transformed into public spaces similar to Kathipara Urban Square.
Lines
The Chennai Metro consists of five colour-coded lines developed under two phases. The Blue and Green lines form the Phase I network, while the Purple, Yellow and Red lines are part of the Phase II expansion. The three Phase II corridors have a combined planned length of 118.9 kilometres.
The Blue Line connects Wimco Nagar Depot with Chennai International Airport. It passes through areas including Washermanpet, Chennai Central, Government Estate, Thousand Lights, Teynampet, Saidapet, Guindy and Meenambakkam. The line comprises both elevated and underground sections and provides interchange with the Green Line at Chennai Central and Alandur.
The Green Line extends approximately 22 kilometres from Chennai Central to St. Thomas Mount. The line passes through Egmore, Kilpauk, Anna Nagar, Koyambedu, Vadapalani, Ashok Nagar and Alandur. It includes elevated and underground sections and connects with the Blue Line at Chennai Central and Alandur.
The Purple Line is an under-construction line extending 45.8 kilometres from Madhavaram Milk Colony to Siruseri SIPCOT. The corridor is planned to have 50 stations, including 30 underground and 20 elevated stations. It passes through central Chennai and follows Old Mahabalipuram Road through Perungudi, Thoraipakkam and Sholinganallur, serving the city's southern information technology corridor.
The Yellow Line extends 26.1 kilometres from Lighthouse to Poonamallee Bypass. The line is planned to have 30 stations, including 12 underground and 18 elevated stations. Its route passes through Mylapore, T. Nagar, Kodambakkam, Vadapalani and Porur. The underground section includes stations at Lighthouse, Alwarpet, Nandanam and Panagal Park, while the western section is elevated.
The Red Line is an under-construction line planned to extend 47 kilometres from Madhavaram Milk Colony to Sholinganallur. It will comprise 48 stations, including 42 elevated and six underground stations. The corridor passes through northern and western Chennai before continuing towards the southern suburbs. It will connect with Corridor 3 at Sholinganallur, where a multi-level interchange station is being developed.
Chennai Metro runs on 1,435mm (4ft8+1⁄2in) standard gauge and the lines are double-tracked. The trains can operate at a maximum speed of 120km/h (75mph), and the average operational speed is 85km/h (53mph).
As of October 2026, the operational network consists of three colour-coded lines covering a length of 68.8km (42.8mi).
Alstom supplied the rolling stock for the first phase of the Chennai Metro. For the first phase, it supplied 42 train-sets composed of four coaches. The first nine train sets were imported from Brazil and the rest were manufactured at Alstom's facility at Sri City near Chennai. The trains are air-conditioned with electrically operated automated sliding doors. The trains usually have a first class compartment and a dedicated section reserved for women.
The trains operate on 25 kV ACelectric traction. The trains are connected to the grid via overhead lines and are equipped with regenerative braking with a capacity to recover 30–35% of the energy during braking. The electricity is supplied by the Tamil Nadu Electricity Board, and the metro system consumed an average of 70 MW of power daily in 2014. Chennai Metro also uses solar power with an installed capacity of 6.4 MWp, which contributed to about 12-15% of the energy requirement of the metro in 2023.
For the second phase, Alstom was awarded a ₹9.47 billion (US$98million) contract to supply 26 trainsets made of three coaches each to be deployed on the Yellow Line. In November 2024, CMRL awarded a ₹36.58 billion (US$380million) contract to BEML for the supply of 70 trainsets, made of three coaches each, to be deployed on Red and Purple lines. In June 2025, CMRL placed an additional order of 32 driverless trainsets with Alstom.
A total of 40 stations, 22 of which are underground, are operational on the two lines of the first phase. In the underground sections, a walkway runs along the length of the corridor with cross passages every 250m (820ft) for the maintenance and emergency evacuation. The underground stations have an average width of 200m (660ft) and are located at an average depth of 6.1m (20ft) from the ground level. The average length of the stations in Phase 1 extension is about 180m (590ft).
The elevated stations have three levels with the concourse level at a minimum height of 5.5m (18ft) above the ground level and platform level above the concourse while the underground stations have two levels and are equipped with platform screen doors. The stations are air-conditioned and are equipped to be disabled and elderly friendly, with automated fare collection, public announcement system, electronic display boards, escalators and lifts. Paid parking facilities are available for two wheelers in most stations and four wheelers in select stations.
Depots
Wimco Nagar depot is situated adjacent to the Wimco Nagar Depot station
Chennai Metro maintains a major depot at Koyambedu which houses maintenance workshops, stabling lines, test tracks and a washing plant for the trains. In 2022, an elevated depot at Wimco Nagar commenced operations with the same facilities. Three new depots at Madhavaram, Poonamallee, and Semmencherry, are planned as a part of the second phase, of which Madhavaram depot is planned to be the largest. The Poonamallee depot was first in Phase II to commence operations with trial runs being conducted since 2024. In 2025, a sixth depot was planned at Pattabiram as a part of the Phase-III expansion of the Chennai Metro.
As of 2022[update], the metro operates trains from 5:00am to 11:00pm. The blue line has an average frequency of every 6 minutes during peak hours and every 12 minutes during off-peak hours. On the green line, the average frequency is 12 minutes during peak hours and 18 minutes during off-peak hours. The main operational control center (OCC) is located in Koyambedu where the movement of trains and real-time CCTV footage obtained is monitored. In 2022-23, the average daily ridership was 0.25 million.
Fare and ticketing
Interior of Chennai Metro coaches
The minimum fare is ₹10 and the maximum fare is ₹50.
There are six types of tickets issued by CMRL for travel in Chennai Metro.
Single journey tokens, which need to be purchased each time for every journey at the ticket counter or in ticket vending machines available at all stations.
Stored value cards (SVC) are pre-paid, rechargeable, travel cards that can be purchased at any ticket counter against a refundable deposit, can be recharged up to at any ticket counter or in automated ticket vending machines at stations and offers discounted fares. In April 2023, National Common Mobility Card replaced the Stored value cards
Trip cards are for applicable for travel between the same two stations and are available in varied combinations and validity with discounted fares.
Tourist cards provide the cardholders unlimited rides on the Chennai Metro system for one day.
QR Tickets for single and return journey tickets can be bought through the CMRL mobile app with QR code ticket scanners at stations.
On 17 June 2015, a 30-year-old man was killed and another motorcyclist injured when an iron rod fell on them at a metro construction site near Officers Training Academy at St. Thomas Mount.
On 27 September 2022, a crane used for transporting iron rods crashed near Ramapuram, causing the rods to fall on a Metropolitan Transport Corporation bus and injuring the bus driver, conductor, and crane operator.
On the night of 13 June 2025, two girders of the under-construction Poonamallee–Porur Metro section collapsed in Manapakkam, killing a 43-year-old man. CMRL imposed a fine of ₹10 million (US$100,000) on the contractor Larsen & Toubro for the incident.
On the early morning of 2 December 2025, a metro train on blue line struck underground between Central Metro station and High Court Metro station due to technical glitches owing to which the passengers onboard got stranded inside the underground tunnel and has been rescued themselves by walking through the inspection catwalk trial.
↑Institutional Development of Suburban Rail systems(PDF) (Report). Indian Railway. p.10. Archived(PDF) from the original on 2 April 2024. Retrieved 1 December 2023. This was appreciated by the Planning Commission way back in 1965, when it took the initiative to set up Metropolitan Transport Teams (MTT) to study the transport problems of the first four metropolitan cities of Bombay, Calcutta, Delhi and Madras and to recommend policies and programs for their improvement.
Bold represents terminal station on the respective main or branch line. Stations in italics are proposed/under construction. Stations in bold and italics are terminal stations proposed/under construction.
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