TBM Assembly Begins for Key Tunnel Section

The assembly of Tunnel Boring Machines (TBMs) has begun for the Mumbai-Ahmedabad High-Speed Rail's most challenging underground section. While the start of work with advanced German machinery signals progress, it also heightens worries about the project's escalating costs and long timeline.

TBM Assembly Underway

National High Speed Rail Corporation Limited (NHSRCL) has started assembling two large Tunnel Boring Machines (TBMs) for the 21-kilometer underground tunnel linking the Bandra Kurla Complex (BKC) and Shilphata. This section is the most technically difficult on the entire 508-km corridor, requiring excavation beneath crowded residential areas and a 7-km stretch under Thane Creek. Assembling each TBM is expected to take at least 97 days.

Rising Costs and Lingering Delays

The project, initially planned for completion in 2023-24, has seen its estimated cost jump 83%, from ₹1.1 lakh crore to nearly ₹1.98 lakh crore. This increase is driven by major delays in acquiring land and higher material expenses. The MAHSR corridor has long faced land acquisition issues, especially in Maharashtra. Worldwide supply chain problems, worsened by events in West Asia, are driving up costs for infrastructure materials like bitumen, steel, and fuel by 15-25%. While advanced TBMs like those from Herrenknecht are necessary for complex geology, their transport and assembly are difficult. Previous delays in TBM deliveries, including machines held in Chinese customs, show how supply chains can affect Indian projects. It's common for large Indian infrastructure projects to face cost overruns exceeding 20% and significant delays due to issues like poor ground studies, contracting methods, and regulatory hurdles.

Persistent Risks: Safety, Debt, and Overruns

The complexity of the Mumbai-Ahmedabad High-Speed Rail's underground section creates a high risk for major cost increases and further delays. TBM assembly is just the first step before difficult excavation begins. Poor studies of ground and soil conditions are a common problem in Indian tunneling projects, leading to delays and cost overruns. The project has reportedly seen safety issues, including a structural collapse in Anand, Gujarat, which killed three workers. NHSRCL and IIT experts are investigating this incident. Critics also question the project's long-term financial health due to its growing debt and high operating expenses. While China has built extensive high-speed rail, its experience also highlights potential debt traps and prioritizing ambition over economic sense, with many routes reportedly losing money. NHSRCL's FY25 revenue was ₹117 crore, against authorized capital of ₹20,000 crore and paid-up capital of ₹15,006 crore, showing a large need for funding.

Revised Timelines and Future Projections

Even with TBM assembly underway, the full 508 km corridor is now expected to open in late 2029. The first section, between Surat and Bilimora, is planned for August 15, 2027. However, the significant engineering challenges, rising costs, and possible unknown geological problems on the BKC-Shilphata section suggest these dates could shift again. The project's success will depend on its ability to manage its estimated ₹2 lakh crore cost and meet the updated schedules.