The kingfisher, particularly the common kingfisher (Alcedo atthis), is renowned for its ability to dive into water with minimal splash, thanks to its streamlined beak. This natural design inspired Japanese engineers to solve a significant challenge faced by the Shinkansen bullet trains.

As the Shinkansen trains increased in speed, they encountered a problem known as “tunnel boom.” When a train entered a tunnel at high speed, it compressed the air inside, creating a shockwave that exited the tunnel with a loud boom, disturbing nearby residents.

Eiji Nakatsu, an engineer and avid birdwatcher, observed that the kingfisher’s beak allowed it to dive into water with barely a splash. He hypothesised that mimicking this design could reduce the tunnel boom effect.

By redesigning the train’s nose to emulate the kingfisher’s beak, engineers achieved remarkable results:

• Noise Reduction: The new design significantly reduced the tunnel boom, making the trains quieter.
• Energy Efficiency: The aerodynamic shape reduced air resistance, resulting in a 15% decrease in electricity consumption.
• Increased Speed: The trains could travel 10% faster without additional energy costs.