Work on the underground stretch of Mumbai metro line-7A has commenced, which will connect Gundavali and Chhatrapati Shivaji Maharaj International Airport (CSMIA).

This metro route constitutes a 3.42 km extension of metro line-7 (red line), which links Dahisar East to Gundavali.

Out of the total 3.42-km alignment, there is a section of twin tunnels that will run underground for 2.49 km.

The Mumbai Metropolitan Region Development Authority (MMRDA) through the civil contractor commenced excavation works using the first Tunnel Boring Machine (TBM), T62, as per a FreePressJournal report.

MMRDA states that the line-7A also includes elevated portions that run parallel to the Western Express Highway and Sahar elevated road. The Airport Colony Metro station is elevated along the Airport Authority of India colony.

According to MMRDA, the sub-structure of the elevated viaduct and station has been completed, and now the tunnel digging has started.

Two TBMs To Be Used For The Twin Tunnels

Two tunnel boring machines will be used to construct the twin tunnels for the underground portion. Both TBMs have been installed at the site, and the initial drive for TBM T62 has begun, reports Indian Express.

The beginning of the initial drive for TBM T60 will begin 30-day after the first TBM. The underground station is expected to be complete by December 2024.

The underground portion of this corridor begins just before the vehicular underpass of Sahar elevated road and connects to the CSMIA Metro station underground.

This section runs parallel to terminal T2 and underground Metro Line-3.

According to a metro official, the tunnelling depth ranges from 20m to 6m from ground level — to facilitate the transition from the underground line to the elevated stretch — connecting the underground CSMIA Metro station with the elevated Airport Colony station in Vile Parle.

Metro 7A Extension

The line-7A, planned as an extension will further augment connectivity and utilisation of the already operational metro line-7.

On 19 January 2023, Prime Minister Narendra Modi inaugurated Mumbai metro rail line-7, along with metro line-2A.

Once operational, the new line will create a seamless connection to CSMIA, offering direct access not only to the airport but also to Mira Bhayandar metro-9 and the Western suburbs metro-2A and 7.

In addition, it will significantly cut down travel times to the airport by 30-60 minutes by establishing a connection between metro line-3 and the international airport.

In conjunction with the planned Metro 8, the corridor will facilitate access to the Navi Mumbai International Airport, thereby further enhancing overall connectivity.