Mumbai-Ahmedabad Bullet Train Project Hits Major Milestone as Second Giant TBM Cutterhead Lowered at Ghansoli

India’s ambitious Mumbai-Ahmedabad Bullet Train project has achieved another major engineering milestone with the lowering of the second Tunnel Boring Machine (TBM) cutterhead at Sawli in Ghansoli near Mumbai. The development marks significant progress in the construction of the crucial 21-kilometre underground tunnel section of the country’s first high-speed rail corridor.

The latest advancement comes just days after the first TBM cutterhead was lowered at Vikhroli, indicating rapid progress in one of India’s most technologically advanced transport infrastructure projects. Officials believe the underground tunnelling phase will become one of the most critical and complex engineering components of the Mumbai-Ahmedabad Bullet Train corridor.

Second TBM to Tunnel From Ghansoli Towards Vikhroli

According to project officials, the second Tunnel Boring Machine will begin its tunnelling journey from Sawli (Ghansoli) and move towards Vikhroli as part of the underground alignment of the high-speed rail project.

Both TBMs are currently undergoing final assembly and commissioning procedures before tunnelling operations officially begin.

Officials stated that the first tunnelling drive is expected to commence during the first week of July 2026 after readiness checks and technical trials are completed.

The underground tunnel section is considered one of the most challenging parts of the entire Mumbai-Ahmedabad Bullet Train project due to dense urban conditions and engineering complexity.

Massive 350-Tonne Cutterhead Installed

The newly lowered cutterhead is one of the most important components of the Tunnel Boring Machine’s main shield assembly.

According to officials, the cutterhead measures approximately 13.6 metres in diameter and weighs nearly 350 tonnes.

The system has been specially engineered to excavate a single tunnel structure designed to accommodate both the up and down lines of the high-speed rail corridor.

The cutterhead has been equipped with 84 cutter discs, 124 scrapers and 16 bucket lips. These components are designed to cut through underground material and efficiently remove excavated soil and debris during tunnelling operations.

Two Giant TBMs Arrive for Underground Bullet Train Section

Officials confirmed that two Tunnel Boring Machines have been received for the underground section of the Mumbai-Ahmedabad Bullet Train project.

TBM 1 weighs approximately 3,080 tonnes, while TBM 2 weighs around 3,184 tonnes.

Both machines are Mix Shield or Slurry-based TBMs equipped with cutterheads measuring 13.6 metres in diameter.

Each TBM stretches approximately 95.32 metres in total length and includes several advanced engineering systems designed for large-scale underground excavation.

Advanced Engineering Systems Installed in TBMs

According to project authorities, each Tunnel Boring Machine includes multiple critical components required for tunnelling operations.

These include the cutter wheel, main bearing, jaw crusher, erector system, main shield, tail shield and four specialised gantries.

Officials stated that the machines are capable of operating at a maximum cutterhead speed of four revolutions per minute (RPM).

The excavation system can achieve tunnelling progress of up to 49 millimetres per minute while maintaining operational safety standards.

The technology is specifically designed to ensure steady excavation in challenging underground conditions beneath Mumbai’s urban landscape.

Underground Tunnel Marks Key Phase of Bullet Train Corridor

The lowering of the second cutterhead represents the final stage in the primary assembly of the TBM’s main shield structure.

Officials described the development as another major engineering milestone for the Mumbai-Ahmedabad Bullet Train corridor, which remains one of India’s biggest transport infrastructure projects currently under construction.

The 21-kilometre underground tunnel section is expected to play a crucial role in connecting Mumbai with the larger high-speed rail network.

Mumbai-Ahmedabad Bullet Train Project Continues Rapid Progress

The latest milestone highlights the accelerating pace of work on the Mumbai-Ahmedabad Bullet Train project as India pushes forward with high-speed rail infrastructure development.

The corridor is expected to transform long-distance travel between Mumbai and Ahmedabad by introducing advanced high-speed rail technology capable of significantly reducing travel time between the two cities.

With the underground tunnelling phase now moving closer to execution, the project is entering one of its most technically demanding stages, showcasing large-scale engineering and infrastructure capabilities on an unprecedented scale in India.