National High-Speed Rail Corporation Limited (NHSRCL) on February 9 opened technical bids for the 21-km underground tunnel from Kalyan Shilphata to Bandra Kurla Complex (BKC) of the Mumbai-Ahmedabad High Speed Rail Corridor, also called the bullet train project.
As part of package two of the project, a 7-km stretch of the 21-km tunnel will be built under the sea at Thane Creek, making it the first undersea tunnel in the country.
Two companies — Afcons Infrastructure Limited and Larsen & Toubro Limited — have participated in the bid, and now final scrutiny is under process. The bid will be closed and the tender will be awarded if it meets the agency’s requirements to complete the most complex part of the project.
The 21-km stretch will be a single-tube tunnel to accommodate twin tracks. The section will include constructing 39 equipment rooms at 37 locations adjoining the tunnel.
Tunnel boring machine with a cutter head of 13.1-metre diameter will be used for construction. Usually, 5-6-metre diameter cutter heads are used for urban tunnels used in Mass Rapid Transit Systems (MRTS) or Metros.
An official statement said three TBMs would be used to make about 16 km of the tunnel, and the remaining 5 km will be through the new Austrian tunnelling method (NATM). Both these technologies were used in Mumbai’s underground Metro Line 3 project, on the route from Colaba to SEEPZ via Bandra.
This tunnel will be about 25-65 metres deep from the ground level, and the deepest construction point will be 114 metres below Parsik hill near Shilphata.
The Mumbai Ahmedabad bullet train project was severely delayed in Maharashtra due to delays in land acquisition. It was alleged that the Maha Vikas Aghadi (MVA) government delayed the land acquisition for the proposed Bandra Kurla Complex (BKC) underground station. Land acquisition in areas such as Palghar and Thane was also delayed. Meanwhile, the project saw massive civil work in progress in Gujarat.
After Eknath Shinde assumed power in Maharashtra with the BJP’s support, the project picked up speed. Mumbai Metropolitan Region Development Authority(MMRDA) handed over the land required for the underground BKC station and other purposes to the NHSRCL.
Mumbai-Ahmedabad bullet train project at a glance
508.17 km of rail track between Mumbai and Ahmedabad, 21 km underground.
A maximum speed of 350 km per hour, covering the 508-km stretch in under three hours.
Japan giving a loan of Rs 88,000 crore to India for the project at a minimal interest of 0.1%.
The mega project is likely to be completed by 2026.
Number of stations: 12
Maharashtra: 4 stations
Gujarat: 8 stations
Stations in Maharashtra: Mumbai (BKC), Thane, Virar and Boisar
Stations in Gujarat: Vapi, Bilimora, Surat, Bharuch, Vadodara, Anand/Nadiad, Ahmedabad and Sabarmati
Number of depots: 3
Maharashtra: 1 (Thane)
Gujarat: 2 (Surat & Sabarmati)
Operational Control Centre: Sabarmati
Land acquisition status
Overall – 98.88% attained
Gujarat – 98.91%
Dadra & Nagar Haveli – 100%
Maharashtra – 98.79%