Mumbai Achieves First Undersea Bullet Train Tunnel Breakthrough With Japanese Tech
India’s ambitious Mumbai-Ahmedabad High-Speed Rail (MAHSR) project, widely known as the bullet train corridor, has achieved a significant engineering milestone with the first breakthrough in its challenging 21-kilometre-long undersea tunnel. This vital section, connecting Ghansoli and Shilphata in Maharashtra, is poised to become a hallmark of India’s inaugural high-speed rail line, driven by advanced Japanese Shinkansen technology. This development underscores the nation’s commitment to futuristic infrastructure that supports sustainable and equitable urban growth.
The Ministry of Railways confirmed this pivotal construction progress on July 14, highlighting the swift development in a project symbolic of India’s high-speed rail future and a testament to Indo-Japanese technological cooperation. The 21-kilometre tunnel includes a challenging 7-kilometre undersea portion beneath Thane Creek, being constructed using a combination of Tunnel Boring Machines (TBM) and the New Austrian Tunnelling Method (NATM). The completion of a 2.7-kilometre continuous NATM section from the Shilphata end marks the project’s first underground breakthrough, conquering one of its most formidable construction obstacles.
This high-speed rail corridor is a cornerstone of India’s vision for a zero net carbon future. By offering a rapid, electrically powered alternative to air travel and conventional trains, it promises to significantly reduce carbon emissions and alleviate congestion on existing transport networks. This shift towards greener mobility solutions is crucial for mitigating climate change impacts and fostering eco-friendly cities, ensuring that economic progress is balanced with environmental responsibility.
Beyond environmental gains, the project is designed to foster more equitable and gender-neutral cities. Dramatically reduced travel times between major economic hubs like Mumbai and Ahmedabad will enhance accessibility for a broader demographic, facilitating easier access to employment, education, and healthcare. This improved connectivity supports greater social inclusion and economic opportunity for all citizens, irrespective of their socio-economic background or gender, by making urban centres more accessible and integrated.
While celebrating this engineering feat, the project has navigated complex challenges. The deployment of three high-capacity German-origin TBMs, essential for excavating the remaining 16 kilometres of the tunnel, has faced delays due to geopolitical tensions impacting their release from a foreign port. Despite these hurdles, the National High-Speed Rail Corporation Ltd. (NHSRCL) has completed several inclined and vertical shafts to facilitate TBM deployment, demonstrating resilience in overcoming logistical obstacles.
Civil works across the entire 508-kilometre corridor are progressing rapidly, with 310 kilometres of viaducts already constructed. Five of the 12 planned stations are complete, with three more in advanced stages of development, alongside 15 completed river bridges. The Bandra-Kurla Complex (BKC) station in Mumbai, a subterranean marvel 32.5 metres below ground, is designed to accommodate a 95-metre-high building above it, showcasing innovative urban integration. The project’s financial backbone is a soft loan from the Japan International Cooperation Agency (JICA), covering 80% of the estimated ₹1.08 lakh crore cost, with the remainder from Indian governments, signifying a unique blend of international cooperation and domestic investment.
Initially slated for completion in August 2022, the project has seen revised deadlines, with partial operations in the Gujarat section expected by 2028 and full corridor commissioning, including Mumbai, targeted for 2030. Once operational, the bullet train is projected to cut travel time between Mumbai and Ahmedabad to just over two hours for non-stop journeys, a substantial improvement over the current seven-hour train ride. This transformative project is not merely a means of transport; it is a tangible symbol of India’s vision for a high-speed, sustainable, and strategically advanced future.
