Mumbai-Ahmedabad Bullet Train: First Tunnel Breakthrough Achieved In BKC-Shilphata Section

Mumbai-Ahmedabad High-Speed Rail (MAHSR) project achieved its first major breakthrough in the 21-kilometre-long tunnel between Bandra-Kurla Complex (BKC) and Shilphata on July 9. This breakthrough marks the successful completion of a 2.7-km continuous tunnel section — the first segment to be completed within this ambitious infrastructure project.

The 21-km tunnel, a critical component of the Mumbai segment of the bullet train corridor, includes a 7-km undersea passage beneath Thane Creek and is being constructed using two advanced tunnelling techniques. A 5-km stretch between Shilphata and Ghansoli is being excavated using the New Austrian Tunnelling Method (NATM), while the remaining 16 km is being constructed using Tunnel Boring Machines (TBMs).

To accelerate progress on the NATM section, engineers constructed an Additionally Driven Intermediate Tunnel (ADIT), enabling excavation to proceed simultaneously from both the Ghansoli and Shilphata ends. So far, approximately 1.62 km has been excavated from the Shilphata side, bringing the total NATM tunnelling progress to around 4.3 km.

Officials have emphasized the strict safety protocols implemented throughout the construction. Ground settlement markers, piezometers, inclinometers, strain gauges, and biometric access control systems have all been deployed to monitor tunnel stability and protect nearby structures, ensuring that tunnelling operations remain safe and controlled.

"Our endeavor is to accelerate the pace of work in the Maharashtra section of the Bullet Train Project immediately after the monsoon and to complete it within the stipulated timeline,” said Vivek Kumar Gupta, Managing Director of NHSRCL. “The successful breakthrough of the 2.7-kilometer tunnel using the New Austrian Tunneling Method is a significant achievement and a testament to the dedication and technical expertise of our team. We take immense pride in having completed this critical stretch ahead of schedule and with the highest quality standards.

"The adoption of internationally recognized safety protocols—such as piezometers, inclinometers, ground settlement markers, load cells, and strain gauges—ensures real-time monitoring and enhanced operational safety. We have also implemented a biometric attendance system to strictly regulate tunnel entry, ensuring that only trained personnel are permitted access. The completion of the 300-meter-long ADIT tunnel further supports our efforts in ensuring accessibility and ventilation" further added Gupta.

"With 2.7 kilometers of the total 21-kilometer tunnel already completed, we are now moving into the next phase, which includes tunnel lining, laying of the reinforced concrete track bed, and prompt initiation of track installation. We remain committed to delivering this strategically important infrastructure with speed, safety, and precision.” he said.

The MAHSR project, being executed by the National High-Speed Rail Corporation Limited (NHSRCL), is set to revolutionize rail travel in India by drastically reducing travel time between Mumbai and Ahmedabad.