India’s first tunnel hood technology for railway tunnels is being introduced on the Mumbai-Ahmedabad Bullet Train corridor, the Ministry of Railways said on Saturday, 13 June.
Tunnel hoods are being installed at the portals of mountain tunnels on the high-speed rail corridor to control pressure waves and reduce noise when trains enter and exit tunnels at very high speeds.
The corridor passes through difficult terrain and includes seven mountain tunnels in Maharashtra and one in Gujarat.
The tunnel hoods will be provided at both ends of these mountain tunnels.
According to the ministry, when a high-speed train enters a tunnel, it pushes a large volume of air ahead of it, creating pressure waves inside the tunnel.
If these waves are not managed properly, they can cause a loud “tunnel boom” when the train exits.
Tunnel hoods act as a transition zone between the open environment and the confined tunnel space.
They allow air to enter and exit more gradually, helping reduce pressure changes and improve the aerodynamic performance of the system.
The ministry said the hoods are designed to minimise tunnel boom and noise from high-speed train movement, lower disturbance to nearby communities, and support safe and efficient operations at speeds above 300 kmph.
A key feature of the tunnel hoods is the use of pressure-relief openings or vents.
These openings allow a portion of compressed air to escape gradually into the atmosphere as a train enters the tunnel, reducing the intensity of pressure waves and maintaining smoother airflow.
Tunnel hoods are commonly used in high-speed rail systems in countries operating bullet trains.
Their adoption on the Mumbai-Ahmedabad Bullet Train Project marks the use of global high-speed rail engineering practices in India’s first bullet train corridor.
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