A major milestone in Mumbai’s metro expansion was achieved as the Mumbai Metropolitan Region Development Authority (MMRDA) completed the breakthrough of a 1.65 km-long underground tunnel on Metro Line 7A, connecting Chhatrapati Shivaji Maharaj International Airport (T2) to Andheri East. The event took place in the presence of Maharashtra Chief Minister Devendra Fadnavis.

Also present were Minister for Skill Development Mangal Prabhat Lodha, MLA Parag Alwani, MMRDA Metropolitan Commissioner Dr Sanjay Mukherjee, and Additional Commissioner Ashwini Mudgal. CM Fadnavis initiated the breakthrough by pressing a button and later reviewed the progress on site.

The tunnel forms part of the downline between the Chhatrapati Shivaji Maharaj International Airport station and Airport Colony station. Once complete, Metro Line 7A will enhance regional connectivity, linking Mira-Bhayander, Vasai-Virar, Thane, and the upcoming Navi Mumbai International Airport (NMIA) to Mumbai’s main airport.

So far, 59% of the project has been completed.

Stretching 3.4 km, Metro Line 7A comprises 0.94 km of elevated and 2.5 km of underground track. It will have two stations, Airport Colony (elevated) and Chhatrapati Shivaji Maharaj International Airport (underground).

The twin underground tunnel spans 2.035 km. The downline tunnel, completed using a Tunnel Boring Machine (TBM) deployed 30 metres below ground in September 2023, involved installing 1,180 specially designed precast concrete rings. The tunnel’s diameter measures 6.35 metres.

The alignment had to navigate complex underground utilities, including Metro Line 3, major water and sewage lines, and elevated roads. Despite these challenges, the breakthrough was completed successfully.

Metro Line 7A will eventually offer Mumbaikars a seamless travel corridor from Colaba to Mira-Bhayander and Vasai-Virar via the international airport.