Mumbai-Ahmedabad Bullet Train Project to Use Ventilated Tunnel Hoods for First Time in India

The Mumbai-Ahmedabad High-Speed Rail corridor is set to incorporate advanced engineering solutions aimed at reducing noise and environmental impacts associated with high-speed rail operations, with the National High Speed Rail Corporation Limited (NHSRCL) announcing the construction of 16 ventilated tunnel hoods across eight mountain tunnels along the route.

The 508-km bullet train corridor , which will support trains travelling at speeds of up to 320 kmph , passes through seven mountain tunnels in Maharashtra and one in Gujarat. According to project officials, the ventilated tunnel hoods are being introduced in India for the first time as conventional railway systems do not encounter the same aerodynamic challenges due to their lower operating speeds.

Experts explained that when a high-speed train enters a tunnel, it pushes a large volume of air ahead of it, generating pressure waves that travel through the tunnel. If left unmanaged, these waves can create a loud "tunnel boom" when the train exits, causing noise disturbances in surrounding areas.

The ventilated hoods are designed to act as a transition zone between open air and the tunnel interior, allowing pressure changes to occur more gradually. Specially designed pressure-relief vents enable a portion of the compressed air to escape, reducing the intensity of pressure waves and improving airflow.

NHSRCL said the technology will help minimise tunnel boom, lower noise levels, reduce disturbance to nearby communities , and enhance passenger comfort and operational safety. The corporation noted that tunnel hoods are widely used in high-speed rail networks worldwide where trains operate at speeds exceeding 300 kmph.

The adoption of the technology reflects the growing use of advanced engineering measures in high-speed rail projects to balance performance requirements with environmental protection and community well-being .