Orange Gate-Marine Drive Tunnel TBM Crosses 7 Railway Tracks in Mumbai
The Mumbai Metropolitan Region Development Authority's Orange Gate–Marine Drive Urban Road Tunnel project has achieved a major milestone after its south-bound Tunnel Boring Machine successfully crossed beneath seven operational Central and Harbour Railway tracks without disrupting train operations.
The complex underground operation was completed beneath one of Mumbai's busiest railway corridors while regular suburban and long-distance rail services continued to run overhead. MMRDA executed the crossing under round-the-clock instrumentation and survey monitoring, following safety protocols in coordination with Central Railway and the Commission of Railway Safety.
The twin underground road tunnel project is being built to connect Orange Gate on the eastern waterfront directly with Marine Drive on the western coast. Construction requires the machine to navigate challenging urban and coastal geological conditions and pass beneath existing transport infrastructure, including railway corridors and Mumbai Metro Line 3.
Described as India's largest slurry shield TBM deployed for an urban road tunnel, the machine was officially launched by Chief Minister Devendra Fadnavis and Deputy Chief Minister and MMRDA Chairman Eknath Shinde on December 3, 2025. Preparatory works followed, including connecting backup systems, calibrating flowmeters, densitometers, and pressure sensors, and testing a probe drill unit.
The initial tunnelling drive began on January 8, 2026, with permanent ring erection starting on January 26 and the initial drive finishing on January 31. The machine shifted to its main drive on February 26, commencing main tunnelling on February 28. By March 26, the TBM had excavated 70 metres of its planned 3,720-metre drive.
The overall project consists of twin tunnels spanning more than 7 km. The first tunnel currently under construction is approximately 3.45 km long and reaches depths of up to 52 metres. Once completed, the underground link will integrate with the Mumbai Coastal Road and Atal Setu, reducing travel time between Orange Gate and Marine Drive to around five minutes.
