Advanced technological system being installed on Bullet Train corridor
By Arun Kumar Das
Mumbai, June 22: As work on the Mumbai-Ahmedabad Bullet Train Project makes progress, an advanced technological system — Tunnel Hood — is being installed to make travel on this high-speed corridor quieter and smoother.
Tunnel hoods are being installed at mountain tunnel portals on the Bullet Train corridor, which marks the first time that such technology has been designed and implemented for railway infrastructure in India.
These are a common feature on high-speed rail networks in countries operating bullet trains, where trains travel at speeds exceeding 300 kmph.
These are designed to minimise tunnel boom and noise generated by high-speed train movement while exiting and lower disturbance to surrounding communities.
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.
Why Are Tunnel Hoods Needed?
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 a train exits the tunnel.
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 hood supports safe and efficient operation of trains travelling at very high speeds.
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.
One of the distinctive features of these tunnel hoods is carefully designed pressure-relief vents or windows.
These windows or openings allow a portion of the compressed air to escape gradually into the atmosphere as a train enters the tunnel. This reduces the intensity of pressure waves, minimises tunnel boom and helps maintain smoother airflow. (BVI)
