Red Line (Chennai Metro)

Phase II

The construction of the first phase of Chennai Metro started in June 2009.^[3] Commercial operations started on the green line in June 2015.^[4][5][6] On 10 February 2019, the extension of blue line was opened, completing the first phase of the metro.^[7]

In July 2016, Government of Tamil Nadu announced that the second phase would have three lines totaling 104 km (65 mi) in length with 104 stations.^[8][9] Two corridors would extend from Madhavaram connecting with Siruseri and Sholinganallur respectively (lines 3 and 5) with the third corridor connecting Koyambedu with Lighthouse (line 4). The fifth line connecting Madhavaram Milk Colony and Sholinganallur will extend to 47 km (29 mi) of which 41.2 km (25.6 mi) would be elevated and 5.8 km (3.6 mi) underground. It will consist of 48 stations including six undergrounds stations.^[10][11] The stations for the second phase were designed to be smaller than the existing stations operational in the first phase.^[12]

On 20 November 2020, foundation stone for the second phase was laid and construction commenced.^[13] In November 2022, Alstom was awarded the contract to supply metro coaches for the phase II expansion.^[14] In May 2023, CMRL announced a revised plan for the second phase revising the station count on the fifth line to 45.8^[a] As per the final plan, the line will extend for 44.6 km (27.7 mi).^[2]

The second phase is estimated to cost ₹632.46 billion (US$6.7 billion) of which initially ₹47.1 billion (US$500 million) was loaned by Japan International Cooperation Agency.^[10][16][17] On 14 February 2021, the Prime Minister of India announced that the government has set aside ₹630 billion (US$6.7 billion) for the construction of phase II and further extension.^[18] The line is expected to be completed by 2028.^[19]

Phase II extension

In 2022, the state government proposed a branch extension for the fifth line from Koyambedu to Avadi, covering an approximate 16.1 km (10.0 mi).^[20] In early 2024, feasibility report was submitted by CMRL for the proposed expansion of the line, green lighting the same.^[21] It was later decided to extend the line till Pattabiram. The Detailed Project Report was approved by the Government of Tamil Nadu in May 2025 and forwarded to the Government of India for final approval. A depot near Pattabiram stretch of Outer Ring Road is also planned as a part of the expansion.^[22][23]