The special braking system is designed with quakes in mind
Japan is beginning trials of the newest and sleekest version of its Shinkansen "Bullet Train" which boasts ear-like air brakes for emergency halts.
The latest model will travel at up to 360km/h (233mph) but is capable of reaching even higher speeds.
Its ears - half-moon shaped fins along the roof - are designed for rapid braking in the event of earthquakes.
The train, expected to be in service by 2011, is a highly-developed version of the original Bullet, launched in 1964.
Since then, the Shinkansen has acquired an enviable record of safety and punctuality.
The new Fastech 360S model has a top speed of 405km/h (250mph).
But the East Japan Railway company, the country's largest rail operator, says creating the world's fastest train was not their only aim.
"The test runs are to see how the technology designed to ensure safety, reduce noise and swaying [works]. Running faster is not the only goal," a spokesman said.
Trial runs are expected between the northern Japanese cities of Sendai and Kamikita cities from Saturday.
The world's fastest trains currently in commercial operation include the Sanyo Shinkansen run by West Japan Railway, the TGV in France and the Eurostar which links London, Brussels and Paris.