Bird: Kingfisher
Mimic: Shinkansen 500 Bullet train
Description:
Japan's high-speed line between Tokyo and Osaka was inaugurated in 1964; the famous Shinkansen 'bullet train' (named for its shape) could reach a speed of 210 kmph. In 1977, sections of the Florence-Rome line became Europe's first high-speed railway at top speed of 250kmph. The entire route was completed in 1992. The national French rail company started its first full high-speed line, between Paris and Lyons, on September 27, 1981, with top speed of 260kmph.
Setups:
Most high-speed trains run on conventional tracks similar to conventional gauge systems, but built with stronger material. The train on such a track is likely to have two synchronised engines (power cars), one at either end. Most receive power from roof-mounted pantographs and overhead supply lines. A large part of route alignment is kept straight to support high speed. Although in most countries these trains operate on dedicated tracks, many can also run on conventional tracks at reduced speeds.
Defects:
Around 1990s, Bullet trains were too noisy. Specially when passing through tunnels they cause enormous decibel of noise, which is due to air pressure (piston effect) and air resistance. Due to this, every 1% faster the train moves, the sound raises by 3%.
Key differentiators:
The more streamlined Shinkansen train not only travels more quietly ,it now travels 10% faster and uses 15% less electricity.
Biomimicry story:
Eiji Nakatsu, an engineer with JR West and a birdwatcher, used his knowledge of the splashless water entry of kingfishers and silent flight of owls to decrease the sound generated by the trains. Kingfishers move quickly from air, a low-resistance (low drag) medium, to water, a high-resistance (high drag) medium. The kingfisher’s beak provides an almost ideal shape for such an impact. The beak is streamlined, steadily increasing in diameter from its tip to its head. This reduces the impact as the kingfisher essentially wedges its way into the water, allowing the water to flow past the beak rather than being pushed in front of it. Because the train faced the same challenge, moving from low drag open air to high drag air in the tunnel, Nakatsu designed the forefront of the Shinkansen train based on the beak of the kingfisher. Engineers were able to reduce the pantograph’s noise by adding structures to the main part of the pantograph to create many small vortices. This is similar to the way an owl’s primary feathers have serrations that create small vortices instead of one large one.
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