CHENNAI: The Chennai Metro Rail Limited (CMRL) on Saturday achieved a major milestone in Phase II tunnelling works, as Tunnel Boring Machine (TBM) Vaigai made a successful breakthrough at the Mandaveli Station shaft.

The tunnelling on the 775-metre stretch between Greenways and Mandaveli stations, part of Corridor-3, began in February 2024. The work is being executed by Larsen & Toubro Ltd. Two TBMs, Vaigai and Noyyal, were deployed for the section, and the breakthrough by Vaigai marks the completion of the up-line tunnel.

The event was witnessed by CMRL Director (Projects) T. Archunan, along with senior officials, including CGM (PP&D) Livingstone Eliazer, GM (Underground) Anto Jos Menachery, GM (Tracks) C Selvam, Consultant CRE Sanjeev Mandal and Project Director (L&T) Jayarama.

The tunnelling was carried out beneath densely populated areas, passing under 75 buildings with an overburden ranging from 9 to 12 metres. The TBM encountered challenging silty sand conditions and required 13 cutterhead interventions, completing the drive in 610 days.

The second TBM, Noyyal, is expected to achieve its breakthrough at Mandaveli next month. This marks CMRL’s third breakthrough in October, following successful completions at RK Salai and Kodambakkam.