Chennai Metro
The Chennai Metro is a rapid transit system serving the city of Chennai, India. It is operated by Chennai Metro Rail Limited, a joint venture between the Government of India and the Government of Tamil Nadu. As of December 2025, the network consists of two operational lines spanning and has 41 underground and elevated stations. The system runs on standard gauge and is powered by overhead electric lines.
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.
As a part of the second phase, three more lines covering a length of are planned and are under construction. The Chennai [Mass Rapid Transit System], 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.
Background
A single electrified line from Chennai Beach to Tambaram began operations in 1931 as part of the Chennai Suburban Railway. Two other rail lines were subsequently built, connecting Chennai Central to Gummidipoondi and Tiruvallur in 1979. In 1965, the Planning Commission evaluated the capacity of the transportation network in major metropolitan cities including Madras, and developed plans for further expansion of transportation amenities. As a result, an initial stretch of the Chennai Mass Rapid Transit System between Chennai Beach and Chepauk opened in 1995 – the first elevated rail line in India. The MRTS later extended to Thirumayilai in 1997, to Thiruvanmiyur in 2004, and to Velachery in 2007. In 2006, a modern metro rail system for Chennai was planned, to be modeled after the Delhi Metro.Planning and construction
Phase I
The Delhi Metro Rail Corporation was tasked to prepare a project report on the implementation of metro 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 with being underground. The first corridor would connect Washermanpet with Chennai International Airport extending for with being underground and the second corridor would connect St.Thomas Mount with Chennai Central extending for with being underground. In December 2007, the Chennai Metro Rail Limited was established as a joint venture between the Governments of India and Tamil Nadu to execute the project. The Planning commission gave in-principle approval for the project in April 2008 with the final approval by the Union Cabinet of Government of India in January 2009. The estimated base cost of the first phase was of which 59% was loaned by Japan International Cooperation Agency. The Government of India contributed 15% of the cost with the Government of Tamil Nadu financed the remaining 21% of the project.In February 2009, a contract was awarded for the construction of a long viaduct along the Inner Ring Road between Koyambedu and Ashok Nagar and construction started on 10 June. In March 2009, a US$30 million contract was awarded to a consortium of five companies headed by French company Egis for technical consultancy on the project. In August 2010, the contract for supplying rolling stock was awarded to Alstom for US$243 million. In January 2011, a joint venture between Larsen and Toubro and Alstom was awarded the contract for design and construction of track works and a depot at Koyambedu for.
Contracts for the construction of underground sections of the first phase were awarded to Gammon India and Mosmetrostroy in February 2011. Subsequently in June, tenders for the elevated stations of the first phase were awarded to Consolidated Construction Consortium. The contract for supply of lifts and escalators was awarded to a joint venture of Johnson Lifts and SJEC Corporation. The contract for power supply and overhead electrification was awarded to Siemens for and contracts for automatic fare collection, tunnel ventilation and air conditioning were awarded to Nippon Signal, Emirates Trading Agency and Voltas respectively. In July 2012, the first tunnel boring machine was launched and by October that year, eleven machines were commissioned to bore tunnels by three consortia – Afcons-Transtonnelstroy, L&T and SUCG.
In August 2012, a construction worker was killed with six others seriously injured due to a crane failure near Pachaiyappa's College and on 10 January 2013, a 22-year-old construction worker was killed with three others injured at a construction site between Alandur and St Thomas Mount. On 6 November 2013, a test run was conducted along a stretch of 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.
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 for mandatory safety approvals. After inspecting the infrastructure, the CMRS submitted the report to the Railway Board in April 2015.
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 I Extension
A northern extension of the blue line was announced in 2014 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 trial runs in December 2020. The line opened for passenger traffic on 14 February 2021, increasing the length of the operational metro system to. The expansion costed of which 57% was loaned by Japan. In 2021, the CMRL proposed a further extension of the blue line to connect the airport with Kilambakkam at an estimated cost of.Phase II
In July 2016, the Government of Tamil Nadu announced that the second phase would have three lines spanning with 104 stations. Two corridors would extend from connecting with Siruseri SIPCOT and respectively with the third corridor connecting Koyambedu with on the Marina beach. In July 2017, the state government announced an extension of Phase II, involving a section from Lighthouse up to with an intersection with the Madhavaram–Sholinganallur line at Alwarthirunagar. The second phase would span 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 of which 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 for the construction of the second phase and its further extension. In May 2021, the CMRL awarded contracts to Tata Group, L&T and HCC-KEC for the construction of various sections of the second phase. In November 2022, Alstom was awarded a contract to supply rolling stock for the second phase. The contract included a provision for the supply of 78 train sets including 36 driver-less trains. In December 2022, a contract for the installation of tracks was given to KEC–VNC and Hitachi bagged the contract for the installation of signalling systems. In January 2023, Rail Vikas Nigam Limited was awarded a contract for the constructions of underground stations and Linxon was given the contract for the installation of electric traction.
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. L&T was contracted for the installation of overhead equipment and control and monitoring systems. Tata Projects was awarded the contract to construct select stations in October. In December, the CMRL awarded the contract to ST Engineering for the installation of platform screen doors in the elevated stations of the second phase. In the same month, Shellinfo was awarded a contract for the installation of automated fare collection systems. In addition to the previously ordered Alstom train-sets, the CMRL invited bids in March 2024 for the supply of 96 train-sets for the second phase., about of the second phase had been completed.
In March 2025, the first trial run on the Phase II network was conducted on a stretch between Poonamallee and Mullaithottam on the proposed Yellow Line. In April 2025, trial runs began on a stretch between Poonamallee and 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. In January 2025, Chennai Metro announced that the operations on to stretch will start in February 2026, with no intermediate stoppages at stations from Alapakkam to Saligramam.
Phase II Extension
In 2022, the state government proposed an extension plan spanning 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,, and 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. In May 2024, the state government proposed a new extension from Madhavaram to Ennore. In August 2024, a new extension from Chennai airport to Poonamallee was proposed to connect the existing airport with the planned new airport at Parandur. 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 and respectively, forwarding to Government of India for final approval.Integration of MRTS
The government proposed to integrate the Chennai Mass Rapid Transit System into the Chennai Metro in 2017. In July 2018, the PwC said that the merger would cost around to convert the rolling stock and install other facilities for the merger. On 11 May 2022, Southern Railway of the Indian Railways granted in-principle approval for the conversion of the MRTS into the metro. The railway would handover the MRTS to the CMRL once the expansion of the MRTS is completed and as of 2024, the extended second phase of the MRTS project, connecting Velachery with St. Thomas Mount was still under construction. Once the takeover is completed, Chennai Metro will upgrade the entire MRTS system including tracks, security, ticketing system and rolling stock.Metrolite
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. 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
The third phase of the Chennai Metro is under planning as a part of the Chennai Comprehensive Mobility Plan. 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.
Infrastructure
Network and lines
Chennai Metro runs on and the lines are double-tracked. The average operational speed is with a maximum speed of.As of December 2025, the operational network consists of two colour-coded lines covering a length of 54.1 km.
Rolling stock
Alstom supplied the rolling stock for the Chennai Metro. For the first phase, Alstom 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 and have a first class compartment with a dedicated section reserved for women.The trains operate on 25 kV AC traction catenary system with a maximum speed of. The trains are connected to the grid via overhead electric cables and are equipped with regenerative braking with a capacity to recover 30–35% of the energy during braking. The metro consumes an average of 70 MW of power daily and the electricity is supplied by Tamil Nadu Electricity Board. Chennai Metro also uses solar power with an installed capacity of 6.4 MWp, which contributes to about 12-15% of the energy requirement of the metro.
For the second phase, Alstom was awarded a contract to supply 26 trainsets made of three coaches each to be deployed on the Yellow Line. In November 2024, CMRL awarded a 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.
Stations
A total of 40 stations, 22 of which are underground, are operational on the two existing lines of Phase 1. In the underground sections, a walkway runs along the length with cross passages every for the maintenance and emergency evacuation. The underground stations have an average width of and average depth of from the ground level. The length of the stations in Phase 1 extension is.The elevated stations have three levels with the concourse level at a minimum height of above the ground level and platform level above the concourse while the underground stations have two levels 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
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 facilities for inspection, emergency repair, and a washing plant. New depots were planned at Madhavaram, Poonamallee, and Semmencherry as a part of the second phase. The Madhavaram depot is planned to be the largest depot of the Chennai metro. The Poonamallee depot was used for conducting trial runs in 2024. In 2025, a sixth depot was planned at Pattabiram as a part of the second phase extension.Operations
, 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 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
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 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.
- National Common Mobility Card, also branded as Singara Chennai card, a stored-value cum debit card launched in 2023 in association with State Bank of India which can be used to access all major other metro and select bus transport systems in India.
Incidents
- 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 on the contractor Larsen & Toubro for the incident.