Construction on underwater high-speed rail tunnel hits new milestone

Construction for an underground system, which features an underwater tunnel, for India’s ambitious Mumbai-Ahmedabad High-Speed Rail Corridor has passed a key milestone, according to local reports.

The National High Speed Rail Company Limited (NHSRCL) previously said the 7-kilometer (4.4 mile) tunnel will consist of a single tube, 13.2 meters (43 feet) in diameter, and will be the first undersea tunnel in the South Asian country. It will be part of a more expansive 21-kilometer-long tunnel in the Indian state of Maharashtra.

According to official specifications from NHSRCL, the twin-track tunnel will be between 25 and 65 meters below ground level and a 13.1-meter diameter cutter head will be used to bore. Construction will be facilitated by three shafts, at approximate depths of 35, 39 and 53 meters.

Secant piling (a process for stabilizing underground excavation areas) has completed at two sites, allowing further construction phases to move ahead, News18 reported. The outlet said excavation work for a third site has been fully completed.

Newsweek has contacted the NHSRCL for comment via email.

Construction for the “challenging” project got underway in June.

“Construction of 21 kilometers of tunnel is one of the most challenging contracts of the Mumbai- Ahmedabad HSR corridor, which includes construction of country’s first twin track under sea rail tunnel of 7 kilometers at Thane Creek,” Shri Rajendra Prasad, managing director of NHSRCL, said in a statement on the company’s website.

The tunnel will be bored under Thane Creek to protect the local environment – a protected sanctuary for flamingos and nearby mangroves.

Also in June, a high-speed rail bridge was erected in the country in the space of just 24 hours. Another part of NHSRCL’s high-speed rail project, the bridge was successfully launched over the Delhi-Mumbai National Expressway near Vadodara, Gujarat.

According to NHSRCL, the undertaking involved 3,000 metric tons of steel, standing 18 meters high and 14.9 meters wide.

What Is the Mumbai-Ahmedabad High-Speed Rail Corridor?

The Mumbai-Ahmedabad High-Speed Rail Corridor, often referred to as the bullet train project, is India’s first high-speed rail line, connecting the major cities of Mumbai and Ahmedabad on the western coast of India.

The concept of the high-speed rail line was first proposed in the early 2000s, with a feasibility study commissioned in 2010. Official approval for the project was granted in 2015, and the foundation stone was laid by Indian Prime Minister Narendra Modi and then-Japanese Prime Minister Shinzo Abe in September 2017​​.

The total cost of the project is estimated to be $15 billion, primarily financed through a $12 billion loan from Japan, with the remainder funded by the Indian government​​.

Do you have a story we should be covering? Do you have any questions about high-speed rail or construction projects in your state? Contact LiveNews@newsweek.com