“Tunnel Boom” – A Phenomenon Where High Speed Trains Entering Tunnels Cause Booming Noises

A “Boom” before the arrival of a high-speed train at the exit of a tunnel in Ingolstadt, Germany. The “tunnel boom” can occur at the exit of railway tunnels used for high-speed trains.

When the train enters a tunnel, the shock wave created travels in the tunnel and reaches the output moments before the train.

When this pulse leaving the tunnel, the air expands rapidly outward, creating a boom.