Ahmedabad (Gujarat) [India], June 14 : Tunnel Hoods are being installed at mountain tunnel portals on the Mumbai-Ahmedabad Bullet Train Project. This is the first time such tunnel hood technology has been designed and implemented for railway tunnels in India.
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.
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.
These tunnels 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 tunnels on the Bullet Train corridor are designed to minimise tunnel boom and noise generated by high-speed train movement while exiting. Lower disturbance to surrounding communities. Support 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.
Tunnel hoods are a common feature on high-speed rail systems in countries operating bullet trains, where trains travel at speeds exceeding 300 kmph. Their adoption on the Mumbai-Ahmedabad Bullet Train Project reflects the use of advanced engineering solutions and international best practices to ensure world-class standards of safety, comfort and environmental performance.