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The railway line is positioned 9.57 metres below the Mithi River bed. Below the river’s flow, the structure passes through slush and brecciated basalt rock layers.
Mumbai Metro Aqua Line 3.
Mumbai Metro Aqua Line 3 has announced that train movement has begun on the Dharavi to Acharya Atre Chowk stretch, heading towards Kotak BKC Metro station.
This 9.77-kilometre stretch includes six stations and is expected to be ready for commercial operations by March 2025, subject to safety checks and certifications, as per One India.
A spokesperson for the project confirmed that trial runs have been successfully completed up to Acharya Atre Chowk. A video of the trial runs, showcasing the stations, was also shared on social media. This development is part of Phase 2A. The final phase, stretching to Colaba, is scheduled to be completed by the end of 2025. Once fully operational, the journey between JVLR and Acharya Atre Chowk will take around 39 minutes.
The project faced major challenges, particularly with the construction under the Mithi River. This was the first time such work was attempted in this type of soil, and there were no previous examples to follow.
The railway line includes a twin-tunnel section beneath the river between Bandra Kurla Complex (BKC) and Dharavi stations. Tunnel boring machines (TBMs), named Godavari 3 and Godavari 4, were used, employing the New Australian Tunnelling Method to excavate sequentially.
Approximately 2 kilometres of the 3-kilometre twin tunnel section runs under an expanded water body, including 500 metres beneath the active Mithi River. To overcome these challenges, custom-designed earth balance machines were used to ensure stability, control water seepage, and prevent land settlement.
To prevent water ingress, a special gasket system was designed for this area. Precast concrete segment rings feature mushroom-type gaskets that ensure watertightness. Additionally, a layer of hydrophilic gaskets expands when in contact with water, enhancing the watertight integrity of the joints.
Station Depths & Locations
Dharavi station, located next to Kotak BKC station, is positioned 18 to 18.5 metres underground. The six stations on this stretch are:
- Dharavi
- Sitaladevi
- Dadar
- Siddhivinayak
- Worli
- Acharya Atre Chowk
