Mumbai-Ahmedabad Bullet Train Project: Second TBM Cutterhead installed at Ghansoli shaft
Mumbai, May 23
In a major milestone for the Mumbai-Ahmedabad High-Speed Rail Corridor, the cutterhead of the second Tunnel Boring Machine was lowered at Sawli near Mumbai on Saturday, marking the completion of the primary assembly phase of the machine's main shield.
The massive cutterhead, measuring 13.6 metres in diameter and weighing around 350 tonnes, this component marks the final step in the primary assembly of the TBM's main shield.
The second TBM will begin its journey from Sawli (Ghansoli) near Mumbai and move towards Vikhroli.
Earlier this week, the cutterhead for the first TBM was also lowered at Vikhroli. Both machines will now undergo final assembly and commissioning trials before beginning their initial drive in the first week of July 2026.
The release stated that the cutterhead, with a diameter of 13.6 metres, is designed to excavate a single tunnel large enough to accommodate both up and down lines of the high-speed corridor. The unit is equipped with 84 cutter discs, 124 scrapers, and 16 bucket lips to efficiently cut and remove muck during excavation.
Two Tunnel Boring Machines (TBMs) have been received for the project. TBM-1 weighs 3,080 tons, while TBM-2 weighs 3,184 tons. Both machines feature a cutter head diameter of 13.6 meters and are of Mix Shield/Slurry-based type, designed for efficient tunnelling in complex ground conditions. Each TBM measures 95.32 meters in total length and comprises several critical components, including the cutter wheel, main bearing, jaw crusher, erector, main shield, tail shield, and four specialised gantries that support tunnelling operations.
These machines can operate at a maximum cutterhead speed of 4 RPM (revolutions per minute), with a maximum excavation rate of 49 mm per minute, enabling steady and controlled tunnelling progress while maintaining high safety standards.
— ANI
Reader Comments
Impressive engineering! 13.6 meters diameter and 3,000+ tons each - these are enormous machines. The fact that they can do both up and down lines in a single tunnel is smart design. Hope our engineers are learning from Japanese technology. 🇮🇳🤝🇯🇵
I'm skeptical about the July 2026 deadline. These projects always get delayed. Remember how many years the Mumbai Metro took? But still, better late than never. At least the technical work seems solid with these German/Japanese TBMs.
As someone who travels between Mumbai and Ahmedabad frequently for work, I can't wait for this! The current train takes 6+ hours. If bullet train cuts it to 2 hours, it will be a game changer for business and tourism. 🚄💨
My only concern is the cost overruns. The project budget has already ballooned from the initial estimate. With 84 cutter discs and 124 scrapers in one TBM, maintenance will be expensive too. Hope the government keeps transparency on expenses.
Amazing progress! 🔧 My father worked on tunneling projects in India in the 90s and he says these modern TBMs are light years ahead. The slurry-based system for complex ground conditions is perfect for Mumbai's geology. Proud to see Indian infrastructure modernizing.
J We welcome thoughtful discussions from our readers. Please keep comments respectful and on-topic.