India’s first high-speed rail project has reached an important construction milestone in Maharashtra with the successful breakthrough of a key mountain tunnel on the Mumbai–Ahmedabad High Speed Rail corridor. The development marks steady progress in one of the most technically demanding sections of the bullet train alignment in the state.
The breakthrough has been achieved at Mountain Tunnel-5, a tunnel measuring about 1.5 km in length, located between the proposed Virar and Boisar high-speed rail stations in Palghar district. This tunnel is the first mountain tunnel to be completed in Maharashtra under the Mumbai–Ahmedabad bullet train project and is among the longest tunnels being constructed in the Palghar region.
The tunnel was excavated simultaneously from both ends and completed within a period of around 18 months using the drill-and-blast construction method. Engineers deployed advanced monitoring systems throughout the excavation process to closely observe ground behaviour and geological conditions. Based on real-time assessments, necessary support measures such as shotcrete lining, rock bolting and lattice girders were installed to ensure structural stability and worker safety. Comprehensive safety arrangements, including ventilation systems, fire prevention measures and controlled access zones, were maintained during construction.
In Maharashtra, work is currently in progress on seven mountain tunnels with a combined length of approximately 6 km. Of these, Mountain Tunnel-1, with a length of 820 metres, has recorded around 15 per cent physical progress, while Mountain Tunnel-2, spanning 228 metres, is in the preparatory stage. Mountain Tunnel-3, which is 1,403 metres long, has achieved about 35.5 per cent completion, and Mountain Tunnel-4, measuring 1,260 metres, has reached roughly 31 per cent progress. Mountain Tunnel-6 and Mountain Tunnel-7 have advanced to about 35 per cent and 28 per cent completion respectively.
Earlier, in September 2025, the project had achieved another major milestone with the completion of its first underground tunnel of nearly 5 km between the Bandra Kurla Complex and Thane.
The Mumbai–Ahmedabad High Speed Rail corridor has a total length of 508 km, of which 156 km lies within Maharashtra. Once operational, the bullet train is expected to cut travel time between Mumbai and Ahmedabad to approximately one hour and 58 minutes. In addition to faster connectivity, the project is expected to generate significant employment opportunities, boost economic activity along the corridor and contribute to lower carbon dioxide emissions compared to conventional road-based transport.
