Whalesbook
Engineering Complex Urban Tunneling
The positioning of the second 13.6-meter diameter cutterhead in Navi Mumbai marks a move from assembly to active excavation for the Mumbai-Ahmedabad High-Speed Rail (MAHSR) corridor. These large Tunnel Boring Machines (TBMs) are designed to bore beneath dense urban areas towards Bandra-Kurla Complex, requiring precise structural integrity. The project uses advanced vibration monitoring and soil stabilization to protect the city's infrastructure and the Mithi River during deep excavation.
India's First Undersea Rail Tunnel
A key part of the project is the 7-kilometer undersea tunnel crossing beneath Thane Creek, the most technically difficult section of the 21-kilometer underground route in Maharashtra. The design uses a single, large-diameter tunnel for both high-speed rail lines, minimizing environmental impact in a coastal zone. Real-time monitoring of seismographs and strain gauges will manage pressure on this undersea segment.
Major Contractors and Funding
While NHSRCL manages the project, Larsen & Toubro (L&T) is the main contractor for critical civil and track work, handling over 50% of track packages, including Shinkansen-style ballastless tracks. The project's industrial scale is supported by funding largely from official development assistance loans provided by Japan.
Project Costs and Delays
The bullet train project, costing over ₹1 trillion for its 508-km corridor, faces scrutiny over its financial viability compared to upgrading existing rail networks. The project has also experienced delays since 2017 due to land acquisition and environmental clearances. Financial analysts debate the passenger volumes needed for profitability. Additionally, efforts are ongoing to mitigate the ecological impact on sensitive areas like the Thane Creek Flamingo Sanctuary.