• On September 20, 2025, a major breakthrough was achieved in the excavation of a 4.8 km undersea tunnel beneath the Mumbai-Thane Creek.
  • This is a significant milestone in the construction of India’s first bullet train corridor under the Mumbai–Ahmedabad High-Speed Rail (MAHSR) Project.
  • Project Executing Agency: National High Speed Rail Corporation Limited (NHSRCL)
  • Tunnel Location: Undersea section between Ghansoli and Shilphata on Mumbai-Thane Creek
  • Total Length of Planned Undersea Tunnel: 21 km

KEY FEATURES OF THE TUNNEL

  • India’s first undersea rail tunnel
  • Constructed using the New Austrian Tunnelling Method (NATM)
  • Includes safety systems:
    • Ground settlement markers
    • Piezometers
    • Inclinometers
    • Strain gauges
  • Built as a single tunnel to accommodate two bullet trains simultaneously

PROJECT STATUS

  • Total Project Cost: ₹1.08 lakh crore
  • Viaduct Constructed: 320 km completed
  • First Operational Section:
    • Surat to Bilimora by 2027
    • Extended to Thane by 2028
    • Reaches Bandra Kurla Complex (Mumbai) by 2029
  • Current Travel Time (Mumbai-Ahmedabad): ~9 hours
  • Planned Bullet Train Time: 2 hours 7 minutes
  • Average Speed: 320 kmph

INTERNATIONAL COLLABORATION

  • Project is backed by Japan, under a high-level partnership
  • E10 Shinkansen – Japan’s next-gen bullet train – to be introduced in India
  • Training for Indian Loco Pilots and Maintenance Staff ongoing in Japan using simulators
Operational Plans
  • Initial Frequency: Every 30 minutes during peak hour
  • Future Frequency: Reduced to 20 minutes, eventually to 10 minutes
  • Fare: Will be "reasonable" and affordable to middle class (exact structure not yet declared)

CHALLENGES

  • Delays:
    • ~5 years delay due to lack of permissions under previous Maharashtra government
    • Cost escalation under discussion with Japanese authorities
  • Cracks in Houses:
    • 78 houses along the corridor developed cracks
    • IIT Bombay survey underway
    • Precaution guidelines being prepared and will be released post-state government approvals

STRATEGIC & ECONOMIC IMPORTANCE

  • Will connect major commercial centres:
    • Mumbai, Thane, Vapi, Surat, Anand, Vadodara, Ahmedabad
  • Expected to:
    • Integrate regional economies
    • Create a multiplier effect, similar to Japan’s Tokyo–Osaka corridor
    • Promote high-speed rail manufacturing, urban development, and employment