New Delhi, July 14 -- Marking a major milestone in the Mumbai-Ahmedabad bullet train project, the first section of the 21-km undersea tunnel between Bandra-Kurla Complex (BKC) and Thane was opened recently, an official statement said.

Out of the total 21 km of tunnel, 5 km between Shilphata and Ghansoli in Maharashtra was constructed using the New Austrian Tunnelling Method (NATM), while the remaining 16 km is being built using Tunnel Boring Machines (TBMs).

The tunnel also includes a 7-km-long undersea section beneath Thane Creek.

The statement said the high-speed train project recently achieved another milestone: constructing a 310 km viaduct.

"Track laying, construction of overhead electrical wires, stations, and bridges is going o...