Planning for the metro started in 2007–08 with construction commencing in February 2009. After testing in 2014, the first segment of the metro between theAlandur andKoyambedu stations on theGreen Line began operations on 29 June 2015. On 21 September 2016, operations on theBlue Line commenced betweenChennai Airport andLittle Mount. The underground stretch fromAG-DMS toWashermanpet of Blue Line opened on 10 February 2019, completing phase 1 of the Metro.
Three more lines covering a length of 118.9 km (73.9 mi) are under construction as part of the second phase. TheChennai Mass Rapid Transit System (MRTS), operated byIndian Railways, is planned to be incorporated into the Chennai Metro. Alight rail has been proposed to connectTambaram on theChennai suburban rail network withVelachery on the MRTS. Further extensions are also planned for the three lines under construction.
TheDelhi Metro Rail Corporation (DMRC) was tasked to prepare a project report on the implementation of metro system in Chennai.[11] TheGovernment of Tamil Nadu approved the first phase of the project in November 2007.[12] The first phase was planned with two lines covering 45.1 km (28.0 mi) with 25 km (16 mi) being underground. The first corridor would connectWashermanpet withChennai International Airport extending for 23.1 km (14.4 mi) with 14.3 km (8.9 mi) being underground and the second corridor would connectSt.Thomas Mount withChennai Central extending for 22 km (14 mi) with 9.7 km (6.0 mi) being underground.[11] In December 2007, theChennai Metro Rail Limited (CMRL) was established as ajoint venture between theGovernments of India and Tamil Nadu to execute the project.[12] ThePlanning 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.[13][12] The estimated base cost of the first phase was₹146 billion (US$1.7 billion) of which 59% was loaned byJapan International Cooperation Agency (JICA). The Government of India contributed 15% of the cost with the Government of Tamil Nadu financed the remaining 21% of the project.[11]
In February 2009, a₹1.99 billion (US$24 million) contract was awarded for the construction of a 4.5 km (2.8 mi) long viaduct along theInner Ring Road betweenKoyambedu andAshok Nagar and construction started on 10 June.[14][15] In March 2009, a US$30 million contract was awarded to a consortium of five companies headed byFrench companyEgis for technical consultancy on the project.[16] In August 2010, the contract for supplyingrolling stock was awarded toAlstom for US$243 million.[17][18] In January 2011, a joint venture betweenLarsen and Toubro (L&T) andAlstom was awarded the contract for design and construction of track works and a depot at Koyambedu for₹4.49 billion (US$53 million).[19][20]
Construction of an elevated section in the first phase in 2011
Contracts for the construction of underground sections of the first phase were awarded toGammon India andMosmetrostroy in February 2011.[21][22] Subsequently in June, tenders for the elevated stations of the first phase were awarded to Consolidated Construction Consortium.[23][24] The contract for supply of lifts and escalators was awarded to a joint venture ofJohnson Lifts and SJEC Corporation.[25] The contract for power supply and overhead electrification was awarded toSiemens for₹3.05 billion (US$36 million) and contracts for automatic fare collection (AFC), tunnel ventilation and air conditioning were awarded to Nippon Signal,Emirates Trading Agency andVoltas respectively.[26][27][28] In July 2012, the firsttunnel 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.[29]
In August 2012, a construction worker was killed with six others seriously injured due to a crane failure nearPachaiyappa's College and on 10 January 2013, a 22-year-old construction worker was killed with three others injured at a construction site betweenAlandur andSt Thomas Mount.[30] On 6 November 2013, a test run was conducted along a stretch of 1 km (0.62 mi) track.[31] The project faced several delays and missed deadlines due to problems with land acquisition and cancellation of construction contracts.[32][33] On 11 January 2014, a crane toppled over, killing a 20-year-old construction worker and seriously injuring another atSaidapet.[34]
Chennai Metro during trials in early 2014
On 14 February 2014, the maiden trial run was conducted betweenKoyambedu andAshok Nagar stations.[35][36] The metro received the statutory speed certification clearance from theResearch Design and Standards Organisation (RDSO) in August that year.[37][38] In January 2015, a report was submitted to the Commissioner of Metro Rail Safety (CMRS) for mandatory safety approvals.[39] After inspecting the infrastructure, the CMRS submitted the report to theRailway Board in April 2015.[40][41][42]
Operations on thegreen line between theAlandur and Koyambedu stations commenced on 29 June 2015.[43] The blue line segment from theAirport andLittle Mount stations commenced operations on 21 September 2016.[44] The first underground section betweenThirumangalam toNehru Park on the green line opened on 14 May 2017,[45] and the extension toChennai central was completed on 25 May 2018 along with the section from theSaidapet andAG-DMS stations on the blue line.[46] On 10 February 2019, the underground stretch from AG-DMS toWashermanpet of blue line was opened, marking the completion of the first phase of the metro.[47]
A 9 km (5.6 mi) northern extension of the blue line was announced in 2014 by the Government of Tamil Nadu. The extension would run from Washermanpet toWimco Nagar and consist of nine stations.[48][49][50] Construction started in July 2016 with trial runs in December 2020.[51][52] The line opened for passenger traffic on 14 February 2021, increasing the length of the operational metro system to 54.1 km (33.62 mi).[53] The expansion costed₹37.7 billion (US$450 million) of which 57% was loaned by Japan.[53] In 2021, the CMRL proposed a further extension of the blue line to connect the airport withKilambakkam at an estimated cost of₹46.25 billion (US$550 million).[54][55]
In July 2016, the Government of Tamil Nadu announced that the second phase would have three lines spanning 104 km (65 mi) with 104 stations.[58][59] Two corridors would extend fromMadhavaram Milk Colony connecting withSiruseri SIPCOT andSholinganallur respectively with the third corridor connecting Koyambedu withLighthouse on theMarina beach. In July 2017, the state government announced an extension of Phase II, involving a section from Lighthouse up toPoonamallee with an intersection with the Madhavaram–Sholinganallur line atAlwarthirunagar. The second phase would span 118.9 km (73.9 mi) with 128 stations.[53][60] 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.[61] In 2019, theMadras High Court questioned the state government on the construction method of the tunnels and its impact on the water bodies.[62] The second phase was estimated to cost₹63.25 billion (US$750 million) of which₹47.1 billion (US$560 million) was loaned by JICA.[53][63][64]
Construction of underground station inMadhavaram a part of the second phase
On 20 November 2020, foundation stone for the second phase was laid and construction commenced.[65] On 14 February 2021,Prime Minister of India announced that the government has set aside₹630 billion (US$7.5 billion) for the construction of the second phase and its further extension.[66] In May 2021, the CMRL awarded contracts toTata Group, L&T andHCC-KEC for the construction of various sections of the second phase.[67] 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.[68][69] In December 2022, a contract for the installation of tracks was given to KEC–VNC andHitachi bagged the contract for the installation of signalling systems.[70][71] 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 ofelectric traction.[72][73]
In May 2023, the CMRL announced minor changes to the lines' alignment and that nine stations would be scrapped in the revised plan.[74] Hence, the total length of the second phase was reduced to 116.1 km (72.1 mi).[75] L&T was contracted for the installation of overhead equipment and control and monitoring systems.[76] Tata Projects was awarded the contract to construct select stations in October.[77] In December, the CMRL awarded the contract toST Engineering for the installation ofplatform screen doors in the elevated stations of the second phase.[78] In the same month, Shellinfo was awarded a contract₹42 crore (US$5.0 million) for the installation ofautomated fare collection systems.[79] 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.[80] As of May 2024[update], about 20 km (12 mi) of the second phase had been completed.[81]
In March 2025, the first trial run on the Phase II network was conducted on a 3 km (1.9 mi) stretch betweenPoonamallee andMullaithottam.[82] In April 2025, trial runs begun on a 10 km (6.2 mi) stretch between Poonamallee andPorur stations on the proposedYellow Line.[83]
In 2022, the state government proposed an extension plan spanning 93 km (58 mi) for the three under construction lines of the second phase. The proposal involved extension ofPurple Line from Siruseri SIPCOT to Kilambakkam,Orange Line from Poonamallee toParandur andRed Line from Koyambedu toAvadi.[85] 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$650 million),₹107.12 billion (US$1.3 billion), and₹67.36 billion (US$800 million) respectively.[86][87] 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 59.7 km (37.1 mi).[86][87][88] In May 2024, the state government proposed a new 16 km (9.9 mi) extension from Madhavaram toEnnore.[89][90] 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.[91][92] In May 2024, theGovernment 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$1.2 billion) and₹159.06 billion (US$1.9 billion) respectively, forwarding toGovernment of India for final approval.[93]
The government proposed to integrate the Chennai Mass Rapid Transit System (MRTS) into the Chennai Metro in 2017.[98] In July 2018, thePwC said that the merger would cost around₹30 billion (US$350 million) to convert the rolling stock and install other facilities for the merger.[99] On 11 May 2022,Southern Railway of the Indian Railways granted in-principle approval for the conversion of the MRTS into the metro.[100] 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.[101][102] Once the takeover is completed, Chennai Metro will upgrade the entire MRTS system including tracks, security, ticketing system and rolling stock.[103]
In 2020, alight rail was proposed to connectTambaram railway station of the existing suburban rail network with Velachery on the MRTS,[104] as part of plans to link the differenturban transit lines in the city.[105][106] Feasibility studies for the project was commissioned in February 2023 by theChennai Unified Metropolitan Transport Authority (CUMTA).[105] 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 existingGuindy metro station.[107] In 2025, the government decided to develop the stretch as a regular metro corridor.[96]
MetroS, the Chennai Metro headquarter building atNandanam
The third phase of the Chennai Metro is under planning as a part of the Chennai Comprehensive Mobility Plan.[108] The CMRL is also involved in the feasibility studies for the development of metro rail transport in the cities ofCoimbatore,Madurai andTiruchirapalli.[109]
CMRL developed theKathipara Urban Square as a multi-modal transport hub with parking and recreational areas.[110] In 2023, the CMRL proposed the development ofCentral Square around its headquarters with commercial complexes and multi-storied buildings.[111] In April 2025, CMRL announced that it has identified public spaces inAdyar andVelachery which can be transformed into public spaces similar to Kathipara Urban Square.[112]
Chennai Metro runs on1,435 mm (4 ft 8+1⁄2 in)standard gauge and the lines are double-tracked.[113] The average operational speed is 85 km/h (53 mph) with a maximum speed of 120 km/h (75 mph).[114]
As of March 2024, the operational network consists of two colour-coded lines covering a length of 54.1 km (33.6 mi).[53][115]
Alstom supplied the rolling stock for the Chennai Metro.[117] For the first phase, Alstom supplied 42train-sets composed of four coaches.[118] The first nine train sets were imported fromBrazil and the rest were manufactured at Alstom's facility atSri City near Chennai.[118][119][120] The trains areair-conditioned with electrically operated automatedsliding doors and have afirst class compartment with a dedicated section reserved for women.[121]
The trains operate on25 kV ACtractioncatenary system with a maximum speed of 120 km/h (75 mph).[122] The trains are connected to the grid via overhead electric cables and are equipped withregenerative braking with a capacity to recover 30–35% of the energy during braking.[123] The metro consumes an average of 70 MW of power daily and the electricity is supplied byTamil Nadu Electricity Board.[124] Chennai Metro also uses solar power with an installed capacity of 6.4MWp, which contributes to about 12-15% of the energy requirement of the metro.[125]
For the second phase, Alstom was awarded a₹9.47 billion (US$110 million) contract to supply 26 trainsets made of three coaches each to be deployed on the Yellow Line.[126][127] In November 2024, CMRL awarded a₹36.58 billion (US$430 million) contract toBEML for the supply of 70 trainsets, made of three coaches each, to be deployed on Red and Purple lines.[128] In June 2025, CMRL placed an additional order of 32 driverless trainsets.[129]
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 250 m (820 ft) for the maintenance and emergency evacuation.[130] The underground stations have an average width of 200 m (660 ft) and average depth of 6.1 m (20 ft) from the ground level.[131] The length of the stations in Phase 1 extension is 180 m (590 ft).[132][133]
The elevated stations have three levels with the concourse level at a minimum height of 5.5 m (18 ft) above the ground level and platform level above the concourse while the underground stations have two levels withplatform screen doors.[134] 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.[135] Paid parking facilities are available for two wheelers in most stations and four wheelers in select stations.[136]
Wimco nagar depot is situated adjacent to the Wimco nagar deport station
Chennai Metro maintains a major depot atKoyambedu 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.[137] New depots were planned atMadhavaram,Poonamallee, andSemmencherry as a part of the second phase.[138][139] The Madhavaram depot is planned to be the largest depot of the Chennai metro.[140] The Poonamallee depot was used for conducting trial runs in 2024.[141] In 2025, a sixth depot was planned atPattabiram as a part of the second phase extension.[142]
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.[143][144] The main operational control center (OCC) is located in Koyambedu where the movement of trains and real-time CCTV footage obtained is monitored.[145] In 2022-23, the average daily ridership was 0.25 million.[146]
The minimum fare is₹10 and the maximum fare is₹50.[147][148]
There are six types of tickets issued by CMRL for travel in Chennai Metro.[149]
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 theStored 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.[150]
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 nearOfficers Training Academy at St. Thomas Mount.[151][152]
On 27 September 2022, a crane used for transporting iron rods crashed near Ramapuram, causing the rods to fall on aMetropolitan Transport Corporation bus and injuring the bus driver, conductor, and crane operator.[153]
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$120,000) on the contractor Larsen & Toubro for the incident.[154]
^Institutional Development of Suburban Rail systems(PDF) (Report).Indian Railway. p. 10.Archived(PDF) from the original on 2 April 2024. Retrieved1 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 initalics are Proposed/Under Construction Stations inBold and italics are terminal stations Proposed/Under Construction
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