India, July 6 -- The Ahmedabad-Mumbai Bullet Train project achieved a significant engineering breakthrough on Sunday as India's largest rail tunnel boring machine (TBM) was launched from the Vikroli shaft, beginning excavation toward the under-construction Bandra-Kurla Complex (BKC) station.

This marks the first TBM deployment for the project's ambitious 21-kilometre underground section in Mumbai. Of this, 16 km between Saki (Ghansoli) and BKC will be constructed using TBM technology, while the remaining 5 km has already been completed using the New Austrian Tunnelling Method (NATM).

The newly launched TBM will bore a single-tube, 6-km-long tunnel that will accommodate both up and down tracks for the high-speed train. The alignment pass...