CHENNAI: The railway line linking Tambaram and beyond, one of the busiest suburban routes, has moved a step closer to a much-awaited upgrade after the Railways invited bids to construct a 21.5-km fourth railway line between Guduvanchery and Chengalpattu.

The work, which is estimated to cost Rs 273.26 crore, covers the construction of the new track and associated bridges and structures, besides signalling, telecommunications, and overhead electrification. The track is designed to support train speeds of up to 160 kmph, and the project has a completion period of 730 days.

The development is part of the proposed fourth line connecting Tambaram-Chengalpattu corridor, which is used by several lakh commuters every day. The Southern Railway had completed the final location survey (FLS) for the 31-km stretch last year, after which the project got the necessary clearance from the Railway Board in 2025.

Presently, the Tambaram-Chengalpattu section is a three-line stretch on the Chennai Beach – Villupuram – Tiruchchirappalli - Kanyakumari mainline, serving both suburban and long-distance mail/express trains. The limited capacity prevents the introduction of additional local services due to its heavy utilisation carrying suburban, Mail/Express, and freight traffic. Because of this, the section experiences frequent congestion, impacting punctuality and capacity expansion. The resultant commuter spillover to road transport chokes the already congested GST Road.

The fourth line will ease congestion, enable the extension of the dedicated suburban grid up to Chengalpattu, and promote a modal shift from road to rail, benefiting both passenger and freight traffic.

Once Tambaram is developed as a major coaching terminal, the new line will meet the future traffic requirements, segregating suburban and Express services, improving operational efficiency, and reducing travel time for passengers, said officials.