Line 3 (Chennai Metro)

The Purple Line or Line 3 is one of the planned lines of Chennai Metro. It is part of the second phase of the project and the under construction line stretches from Madhavaram Milk Colony to Siruseri SIPCOT. The 45.4 km long line will consist of 47 stations, out of which 28 will be underground and 19 will be at grade or elevated.

Phase II
The construction of the first phase of Chennai Metro started in June 2009. Commercial operations started on the green line in June 2015. On 10 February 2019, the extension of blue line was opened, completing the first phase of the metro.

In July 2016, Government of Tamil Nadu announced that the second phase would have three lines totaling 104 km in length with 104 stations. 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 third line connecting Madhavaram Milk Colony and Siruseri SIPCOT will extend to 45.8 km of which 19.1 km would be elevated and 26.7 km underground. It will consist of 50 stations including 30 undergrounds stations. The stations for the second phase were designed to be smaller than the existing stations operational in the first phase.

On 20 November 2020, foundation stone for the second phase was laid and construction commenced. In November 2022, Alstom was awarded the contract to supply metro coaches for the phase II expansion. In May 2023, CMRL announced a revised plan for the second phase revising the station count on the third line to 47. As per the final plan, the fourth line will extend for 45.4 km.

The second phase is estimated to cost inr 632460000000 of which initially inr 47100000000 was loaned by JICA. On 14 February 2021, Prime Minister of India announced that the government has set aside inr 630000000000 for the construction of phase II and further extension.

Phase II extension
In 2022, the state government proposed an extension plan for the third line from Siruseri to Kilambakkam, covering an approximate 25 km. In September 2023, feasibility report was submitted by CMRL for the proposed expansion of the line, green lighting the same. The extension was scrapped due to patronage and profitability concerns.

Stations
under construction