Mumbai–Ahmedabad High-Speed Rail’s Zaroli mountain tunnel in Gujarat is on the brink of completion, marking a key milestone in India’s pioneering high-speed rail project. Located near Zaroli village in Valsad district, the 350‑metre tunnel is the only mountain segment in Gujarat and forms part of a broader initiative of eight such structures, seven of which lie in Maharashtra.
The tunnel’s horseshoe‑shaped bore, measured at 12.6 metres in width and 10.25 metres in height, was excavated using the New Austrian Tunnelling Method (NATM). Engineers overcame challenging geological conditions to break through the rock in October 2023—just ten months after excavation commenced. The structure is now being readied to accommodate twin Shinkansen‑style tracks designed for speeds up to 350 km/h. Experts emphasise the precision required for high‑speed alignment, noting that even small deviations could undermine safety and efficiency. “Stringent geometry controls were applied throughout the tunnel construction to ensure seamless integration with the corridor’s standards,” said a senior NHSRCL official.
The Zaroli tunnel represents the first of eight mountain tunnels along the 508‑kilometre corridor, which connects Mumbai, Thane, Virar, Boisar, Vapi, Billimora, Surat, Bharuch, Vadodara, Anand, Ahmedabad, and Sabarmati. It also dovetails with major earthworks already completed: over 304 km of viaduct, 388 km of pier work, fifteen river bridges, eight steel bridges, five PSC bridges, and 163 track kilometres of embankment, according to recent data released by NHSRCL. Further bolstering progress, the agency has successfully launched its first 40‑metre full‑span pre‑stressed concrete (PSC) box girder in Dahanu, Maharashtra. Taken together, these achievements reaffirm NHSRCL’s commitment to delivering India’s first high‑speed rail line on schedule, while supporting eco‑efficient, sustainable transport infrastructure.
Looking ahead, the remaining seven mountain tunnels—located primarily under Palghar district—are expected to be completed ahead of final commissioning in 2028. NHSRCL emphasises that each milestone not only brings the bullet train project closer to fruition but also models green, equitable urban mobility.
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