Chennai Metro Phase 2: North Chennai Gets Ready to Move

Chennai's northwestern suburbs are on the verge of a connectivity leap. Under Chennai Metro Rail Limited's expansion plans, a branch line will run from Koyambedu to Pattabiram via Ambattur and Avadi, and it comes bundled with more than just train tracks. By 2030, Chennai Metro Rail Limited will extend the Phase II corridor from Koyambedu to Pattabiram via Ambattur and Avadi, integrating three state highway flyovers and a new multi-modal transit hub at Avadi, according to a Times of India report.

This branch sits within the larger Phase 2 programme that the Union Cabinet cleared in late 2024. The Union Cabinet approved the Chennai Metro Rail Project Phase-II, comprising three corridors, with the total length of the approved lines around 119 kilometres with 128 stations, at a project completion cost of Rs 63,246 crore. The approved corridors will connect North to South and East to the West of Chennai. The Ambattur-Avadi branch falls under this North-West arm of the network.

On the technical side, the branch line has been formally designated Line 5B. A branch line of corridor five, known as Line 5B, from Koyambedu to Pattabiram has been proposed with its Detailed Project Report approved by the Government of Tamil Nadu in May 2025, and the 21.76 km branch line will consist of 19 elevated stations. This is an upgrade on an earlier feasibility study, which had scoped a shorter alignment. That earlier study covered a 16.07 km elevated metro link connecting key areas including Thirumangalam, Mugappair, and Ambattur, with 15 elevated stations. The plan was to construct it as a branch of Chennai Metro's Line-5, with a detailed feasibility report by L&T Infrastructure Engineering in mid-2023 estimating the construction cost at approximately Rs 6,376.18 crore.

A parallel proposal has also been on the table for extending an existing corridor toward Avadi. As part of the Chennai Metro Phase 2 extension project, the government decided on an extension of corridor 5 from Thirumangalam to Avadi via Mogappair and Ambattur. Whether this materialises as a separate extension or gets folded into the Line 5B branch, the direction is the same: Ambattur and Avadi are firmly on CMRL's expansion radar.

What makes this corridor notable is the infrastructure bundling. State Highways Chief Engineer S Jawahar Muthuraj confirmed that the metro viaduct will share pillars with three flyovers planned along the Chennai-Tiruttani Highway. That shared construction should mean faster execution and less prolonged road disruption compared to building each structure separately.

The connectivity payoff extends well beyond Ambattur and Avadi themselves. For residents of Tiruvallur, Tiruttani and Arakkonam, who currently rely on suburban trains to reach the city centre, the new line will provide direct metro access to Chennai Central, Egmore and even the airport through the interchange at Koyambedu. A multi-modal hub at Avadi means bus, suburban rail and metro users converge at one point, cutting the number of transfers for anyone travelling from the northwest corridor into the city.

For homebuyers, this kind of infrastructure commitment tends to move markets ahead of the actual train service. Property near an operating or soon-to-open metro station doesn't wait for the full network to open before it moves; it moves the moment construction cranes appear and stays elevated well after the first train runs. Ambattur's industrial estate and Avadi's residential belt, both currently reliant on road transport, stand to benefit from exactly this pattern once construction visibly picks up.

Avadi already has an established residential base that this corridor will only strengthen. Mahindra Happinest Avadi, located off Poonamallee-Avadi High Road, is a case in point. The location has excellent connectivity and is less than 15 minutes from Porur and Ambattur IT Parks as well as bus and metro stations near existing and upcoming communities. As Line 5B construction progresses through the decade, residents here will see their commute options expand well beyond what road infrastructure alone currently offers.