Second TBM begins excavation for Mumbai-Ahmedabad bullet train

India's first undersea rail tunnel moved a step closer as the second Tunnel Boring Machine began excavation for the Mumbai-Ahmedabad Bullet Train project beneath Thane Creek in Maharashtra. The 7-km undersea section is part of a 21-km underground corridor. The 3,200-tonne Mixshield TBM features advanced safety, monitoring and waterproofing systems for challenging geological conditions.