Mumbai-Thane tunnel completed for bullet train project

A 2.7 kilometre continuous tunnel section between Bandra Kurla Complex in Mumbai and Shilphata in neighbouring Thane has been successfully completed, giving a major boost to the USD multi-billion Mumbai-Ahmedabad bullet train project, the National High-Speed Rail Corporation Limited (NHSRCL) said on Thursday.

The first breakthrough in the 21 km long tunnel was recorded on Wednesday, a NHSRCL release informed.

This achievement marks a significant leap forward in India's first bullet train project, aimed at connecting Mumbai and Ahmedabad with a high-speed rail corridor, drastically reducing travel time and enhancing transport efficiency between the two financial hubs, it said.

"The 21-kilometre tunnel will be a key part of the high-speed rail corridor, with 16 km being constructed using Tunnel Boring Machines (TBMs), and the remaining 5 km through the New Austrian Tunnelling Method (NATM), especially between Shilphata and Ghansoli. Significantly, the tunnel also features a 7 km undersea section beneath Thane Creek," it said.

"To expedite tunnelling in the NATM portion, an Additionally Driven Intermediate Tunnel (ADIT) was constructed, which enabled simultaneous excavation from both Ghansoli and Shilphata ends. Of the total NATM section, approximately 1.62 km has been excavated from the Shilphata side, and the cumulative progress stands at 4.3 km," the release informed.

Comprehensive safety measures have been implemented at the site, including installation of ground settlement markers, piezometers, inclinometers, strain gauges, and biometric access control systems, the NHSRCL said.

These are designed to ensure safe and controlled tunnelling operations without impacting nearby infrastructure or habitats, it added.