Mumbai Ahmedabad Bullet Train: 7-km Undersea Tunnel Hinges on Arrival of Chinese TBMs

Work on the Mumbai Ahmedabad Bullet Train project, India's first high-speed rail corridor, is progressing on multiple fronts, but the crucial underground stretch in Mumbai is awaiting the arrival of three tunnel boring machines (TBMs) from China.

Officials of the National High Speed Rail Corporation Limited (NHSRCL) confirmed that over 60 per cent of the parts required for the first TBM have reached India, with the remaining components expected shortly. The other two machines, however, remain stuck at ports in China. All three were manufactured at Herrenknecht AG's China unit in mid-2024, and there is no clarity yet on when the pending equipment will arrive.

These TBMs are required for the 21-km tunnel between Shilphata and Bandra Kurla Complex (BKC), which includes a 7-km undersea section beneath Thane Creek. So far, nearly 5 km of tunnelling between Shilphata and Ghansoli has been completed using the New Austrian Tunnelling Method (NATM). The remaining 16 km, including the undersea stretch leading to BKC, will be executed using TBMs once deployed.

Completion of the second tunnel MT-6 in Palghar

While the Mumbai underground section waits for full-scale TBM operations, construction in Palghar district has recorded visible progress. On February 3, 2026, a breakthrough was achieved in the second mountain tunnel (MT-6), measuring 454 metres in length and 14.4 metres in width. Excavated from both ends using NATM, the tunnel was completed within 12 months. This followed the January 2 breakthrough of MT-5 at Saphale.

Seven mountain tunnels are under construction in Palghar. Two have achieved breakthroughs, while the remaining are at varying stages of completion. Project officials have indicated that breakthroughs in the remaining tunnels are targeted by August.

In a written reply in the Lok Sabha on February 4, Railway Minister Ashwini Vaishnaw provided an update on overall progress and integration plans. He said the BKC station of the Mumbai Ahmedabad Bullet Train will be integrated with Mumbai's suburban railway network and Metro Line-2B and Metro Line-3 through pedestrian connectivity to ensure seamless passenger movement.

Responding to queries regarding trial runs on the Vapi-Virar-BKC section, the minister said timelines can be determined only after completion of civil structures, track work, electrification, signalling, telecommunications and trainset supply.

The 508-km corridor runs through Maharashtra, Gujarat and the Union Territory of Dadra & Nagar Haveli, covering 12 stations from Mumbai to Ahmedabad. Foundation work has been completed at eight stations in Gujarat, while work continues at Thane, Virar and Boisar in Maharashtra. Excavation at BKC is nearing completion and base slab casting has begun.

Around 334 km of viaducts, 17 river bridges and 12 major crossings have been completed. Track laying and electrification have accelerated in Gujarat, while in Maharashtra, the Vaitarna river bridge has reached pier level and foundation work on rivers such as Ulhas and Jagani has been completed. Depot works at Thane, Surat and Sabarmati are also in progress.

With mountain tunnelling advancing and elevated sections nearing completion in several stretches, the arrival of the remaining TBMs will be critical for pushing forward the underground Mumbai section of the Mumbai-Ahmedabad Bullet Train.

Mumbai Ahmedabad Bullet Train Update as of February, 2026:

• 334 km of viaduct completed
• 17 river bridges completed
• 12 major crossings over highways and railways completed
• Track laying and electrification progressing rapidly in Gujarat
• Longest river bridge in Maharashtra over Vaitarna has reached pier level
• Major rivers such as Ulhas and Jagani have completed foundation-level work, while civil construction continues at all four Maharashtra stations.

Mumbai Ahmedabad Bullet Train: How many Stations on the Corridor?

Mumbai (BKC), Thane, Virar, Boisar, Vapi, Bilimora, Surat, Bharuch, Vadodara, Anand, Ahmedabad and Sabarmati.

Foundation work has been completed at eight stations in Gujarat, while work is progressing at Thane, Virar and Boisar. Excavation at BKC is nearing completion, and base slab casting has commenced.