Mumbai-Ahmedabad Bullet Train Project: What are tunnel hoods and why are they needed?

Mumbai-Ahmedabad bullet train project update: As India's first bullet train corridor takes shape, the Mumbai-Ahmedabad High-Speed Rail Project is adopting innovative tunnel hood technology. Here's why

Mumbai-Ahmedabad bullet train project latest update: The National High-Speed Rail Corporation Limited (NHSRCL) is working in full swing on the country’s first bullet train corridor, which will connect Mumbai and Ahmedabad. The 508-km-long High-Speed Rail (HSR) corridor passes through Maharashtra, Gujarat and Dadra & Nagar Haveli.

As part of the Mumbai-Ahmedabad HSR Project, the NHSRCL is now installing ‘tunnel hoods’ at the portals of mountain tunnels. “This is the first time such tunnel hood technology has been designed and implemented for railway tunnels in Bharat.

The Mumbai–Ahmedabad Bullet Train corridor traverses challenging terrain and includes seven mountain tunnels in Maharashtra, and one mountain tunnel in Gujarat. Tunnel hoods are being provided at both ends of these mountain tunnels. ” it said.

As tunnel hood technology is being introduced in India for the first time, it is quite interesting to know about what these structures are and how it works. According to NHSRCL, the tunnel hoods are designed to mitigate the tunnel boom effect caused by pressure waves generated by high-speed trains. It is an advanced engineering solution adopted to ensure smoother train operations and enhanced passenger comfort.

NHSRCL said that when a high-speed train enters a tunnel, it pushes a large volume of air ahead of it, similar to a piston moving inside a cylinder. “This sudden compression of air generates pressure waves that travel through the tunnel. If not properly managed, these pressure waves can create booming noise, when train exists the tunnel,” it noted.

Thus, the tunnel hoods act as a transition zone between the open environment and the confined tunnel space. By allowing air to enter and exit more gradually, they help control pressure changes and improve the overall aerodynamic performance of the system.

The tunnel hoods on the Bullet Train corridor are designed to:

“In simple terms, the tunnel hood helps the train and the air adjust to each other gradually rather than abruptly, making high-speed rail travel quieter, smoother and more comfortable,” the NHSRCL said.

Anish Mondal is a journalist with over nine years of experience covering the railways and roadways. Currently a member of the Indianexpress.com editorial team, Anish specializes in high-impact sectors. Professional Journey Anish began his career at the public broadcaster Rajya Sabha Television (now Sansad TV), where he developed a foundational understanding of legislative processes and national governance. In 2018, he transitioned to digital financial journalism at FinancialExpress.com, spending nearly six years refining his expertise in market trends and corporate reporting. Before joining The Indian Express in 2025, he served as a key contributor at ETNowNews.com. Education & Expertise Anish’s reporting is backed by a rigorous academic background in communication and the humanities: Master of Journalism and Mass Communication (MJMC) – Apeejay Stya University Post Graduate Diploma in Journalism and Production (PGTVRJP) – Apeejay Institute of Mass Communication Bachelor of Arts (English Honours) – University of Calcutta Areas of Coverage Connectivity: Detailed reporting on the expansion of Indian Railways and National Highway networks. ... Read More

Mumbai-Ahmedabad bullet train project latest update: The National High-Speed Rail Corporation Limited (NHSRCL) is working in full swing on the country’s first bullet train corridor, which will connect Mumbai and Ahmedabad. The 508-km-long High-Speed Rail (HSR) corridor passes through Maharashtra, Gujarat and Dadra & Nagar Haveli.

As part of the Mumbai-Ahmedabad HSR Project, the NHSRCL is now installing ‘tunnel hoods’ at the portals of mountain tunnels. “This is the first time such tunnel hood technology has been designed and implemented for railway tunnels in Bharat.

The Mumbai–Ahmedabad Bullet Train corridor traverses challenging terrain and includes seven mountain tunnels in Maharashtra, and one mountain tunnel in Gujarat. Tunnel hoods are being provided at both ends of these mountain tunnels. ” it said.

As tunnel hood technology is being introduced in India for the first time, it is quite interesting to know about what these structures are and how it works. According to NHSRCL, the tunnel hoods are designed to mitigate the tunnel boom effect caused by pressure waves generated by high-speed trains. It is an advanced engineering solution adopted to ensure smoother train operations and enhanced passenger comfort.

NHSRCL said that when a high-speed train enters a tunnel, it pushes a large volume of air ahead of it, similar to a piston moving inside a cylinder. “This sudden compression of air generates pressure waves that travel through the tunnel. If not properly managed, these pressure waves can create booming noise, when train exists the tunnel,” it noted.

Thus, the tunnel hoods act as a transition zone between the open environment and the confined tunnel space. By allowing air to enter and exit more gradually, they help control pressure changes and improve the overall aerodynamic performance of the system.

The tunnel hoods on the Bullet Train corridor are designed to:

“In simple terms, the tunnel hood helps the train and the air adjust to each other gradually rather than abruptly, making high-speed rail travel quieter, smoother and more comfortable,” the NHSRCL said.