The kingfisher and the bullet train

 

Challenge: design a quieter high-speed trainStreet in Tokyo © Andres Ojeda, www.sxc.hu

Natural inspiration: kingfisher Alcedo atthis

 

 

Japan’s high-speed railway network, the Shinkansen, began commercial operation in 1964.  The Shinkansen network now connects Toyko with most of Japan’s major cities.  The busiest section of the line runs between Tokyo and Osaka and carries 409,000 passengers per day – 149 million per year. 1Tokyo © Alexander Chechetkin, www.sxc.hu

 

 

 

 

 

 

 

Shinkansen trains are among the fastest in the world, travelling at up to 300 kilometres per hour. 2  In its early days, the network had a noise pollution problem.3   When a train travels through a tunnel, a cushion of air builds up pressure in front of it.  On exiting the tunnel, the air rapidly expands.  When a Shinkansen train exited a tunnel, the bang caused by the expanding air was enough to disturb people living a quarter of a mile away. 4Kingfisher © Iana55/ Dreamstime

 

 

 

 

 

 

Kingfishers experience a comparable change in pressure when they dive from the air into water to catch fish.  The birds create very little splash when they enter the water due to the aerodynamic shape of their head and large beak. Shinkansen © Razanjp/ Dreamstime

 

 

 

 

 

 

 

 

 

Imitating the kingfisher's shape, engineers equipped trains with a tapering nose nearly 50 feet long.  As well as producing much less noise when exiting tunnels, the newly-designed train used 15% less electricity while travelling 10% faster.4  Shinkansen train technology is cutting-edge, and the Japan Railways Group prides itself on the speed, reliability and smooth ride the trains offer. 1

 

 

Kingfisher © Dirkr/ Dreamstime

 

 

 

There are approximately 95 species of kingfisher (Alcedinidae) in the world, of which 11 species are listed as vulnerable or worse in the IUCN's Red List.  The common kingfisher is the only species found in the UK, living near rivers and lakes and fishing from perches over the water.  Many of the other kingfisher species are found in forest or grassland, swooping down from their perches to catch large insects.  All the kingfisher species are colourful, but the common kingfisher is among the most vivid with its iridescent blue plumage.  Kingfishers demonstrate how natural selection has found the best shape for a particular job, saving human engineers a lot of time and effort to develop a solution for this challenge.

 

 

 

 

 

 

 

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References
1. Central Japan Railway Company: about the Shinkansen.  Accessed February 2010.

2. Railway Technology: Shinkansen N700 model.  Accessed February 2010.
3. Kikuchi, I. (1988) Research and achievements in countermeasures for Shinkansen noise.  Journal of Sound and Vibration 120: 381- 389
4. Biomimicry Institute: transportation.  Accessed Februrary 2010. 
5. Birdlife International: kingfisher species. Accessed February 2010. 

 

Watch videos of kingfishers diving at the Arkive website.  Accessed February 2010.