NHSRCL Signs Contract for India’s First Undersea Rail Tunnel

In a groundbreaking development, the National High-Speed Rail Corporation Limited (NHSRCL) has officially signed a contract with M/s Afcons Infrastructure Limited today. The contract marks a significant milestone in the construction of a 21 km long tunnel, including India’s first-ever 7 km long undersea rail tunnel, in Maharashtra for the Mumbai-Ahmedabad High-Speed Rail Corridor under the MAHSR C-2 package.

The tender for this ambitious project saw its technical bids opened on February 9, 2023, followed by the financial bids on April 6, 2023. Rajendra Prasad, the Managing Director of NHSRCL, expressed his excitement about the project, acknowledging its immense complexity. He stated, “The construction of the 21 km tunnel is one of the most challenging contracts of the Mumbai-Ahmedabad HSR corridor, which includes building the country’s first twin-track undersea rail tunnel spanning 7 km at Thane Creek. The construction of this tunnel will utilize three Tunnel Boring Machines and the innovative New Austrian Tunnelling Method.”

Key Features of the Project:

1. Length and Location: The 21 km long tunnel will stretch between the underground station at Bandra-Kurla Complex and Shilphata in Maharashtra.
2. India’s First Undersea Rail Tunnel: A groundbreaking feat, the project includes the construction of a 7 km (approx.) undersea tunnel at Thane Creek, making it the first undersea rail tunnel in the country.
3. Twin-Track Capability: The tunnel will comprise a single tube capable of accommodating twin tracks for both up and down directions. Additionally, 39 equipment rooms at 37 different locations will be constructed adjacent to the tunnel.
4. Advanced Machinery: The construction will employ Tunnel Boring Machines with a cutter head diameter of 13.1 meters. Typically, urban tunnels, such as those used in metro systems, use cutter heads with a diameter of 5-6 meters. Three Tunnel Boring Machines will be used to construct approximately 16 km of the tunnel, while the remaining 5 km will be built using the New Austrian Tunnelling Method.
5. Depth and Shaft Construction: The tunnel will be situated at depths ranging from 25 to 65 meters below the ground level. To facilitate construction, three shafts will be built at BKC, Vikhroli, and Sawli at depths of approximately 36, 56, and 39 meters, respectively. Additionally, an inclined shaft measuring 42 meters at Ghansoli and a tunnel portal at Shilphata will aid in constructing around 5 km of the tunnel using the NATM tunnelling method.

Tender Status in Maharashtra:

• Mumbai HSR Station [MAHSR Package C-1]: The contract agreement for this project was signed on March 20, 2023.
• Construction of tunnel for double line between Mumbai HSR Station and Shilphata (21 km approx.) [MAHSR Package C-2]: The contract agreement for this vital tunnel construction was signed today, May 8, 2023.
• Civil & building works with 3 nos. of stations, namely Thane, Virar, and Boisar, between Shilphata and Zaroli village on the Gujarat-Maharashtra border (135 km) [MAHSR Package C-3]: Technical bids for this project were opened on April 12, 2023.

The signing of the contract for the construction of India’s first undersea rail tunnel represents a significant leap forward for the Mumbai-Ahmedabad High-Speed Rail Corridor. This groundbreaking infrastructure project is set to revolutionize