India Launches Largest Rail Tunnel Boring Machine in Mumbai

The National High Speed Rail Corporation Limited (NHSRCL) launched India's largest rail tunnel boring machine (TBM) in Vikhroli, Mumbai, on July 5, 2026. The 3,100-tonne Mixshield TBM, featuring a 13.6-metre-diameter cutterhead and a length of 96 metres, began excavating a 6-km single-tube tunnel toward the Bandra Kurla Complex station. This operation is part of a 16-km TBM section between Sawli and the Bandra Kurla Complex, situated within a broader 21-km underground segment in Mumbai.

To facilitate the project, the NHSRCL constructed a 56-metre-deep shaft at Vikhroli and an 11.17-hectare casting yard in Mahape, Thane, where 77,000 concrete segments are being manufactured. The TBM uses advanced slurry-type technology and double-layer EPDM gaskets to maintain a waterproof structure and minimize surface disruption while passing beneath dense urban infrastructure and the Mithi River.

Tunnelling to the Bandra Kurla Complex is expected to finish by early 2027, with the Vikhroli-Ghansoli stretch projected for completion by March 2028. A formal launch event planned by Union railway minister Ashwini Vaishnaw was cancelled due to a red alert for heavy rainfall in Mumbai.