Central Japan Railway Co. (JR Tokai) said it will raise the maximum speed on the Tokaido Shinkansen Line from 270 kph to 285 kph next spring, the first such increase in 23 years.
The greater speed under the revised timetables will cut two to three minutes off the fastest service between Tokyo and Shin-Osaka stations, which currently takes 2 hours and 25 minutes.
The transport ministry in July authorized JR Tokai to increase the maximum operating speed of its N700 Series and N700A Series bullet trains on the Tokaido Line.
“We’ve improved the motor power output, train controls, braking systems and noise reduction capabilities of the Shinkansen, step by step,” a JR Tokai official said. “The increase of the maximum speed by 15 kph was achieved through the accumulation of these efforts.”
The 700 Series, which entered service in 1999, could travel at 285 kph on the Sanyo Line. The improved N700 Series, introduced in 2007, is allowed to operate at 300 kph on the same line.
But the maximum speed had been kept at 270 kph on the Tokaido Line because the curves are significantly sharper than those of other lines. The minimum curve radius on the Tokaido Line is 2.5 km, compared with 4 km on other bullet train lines.
“Even if trains can accelerate on straight rails, they are constantly forced to slow down due to the numerous curves,” said Kei Sakanoue, manager of the Rolling Stock Department at JR Tokai. “Constant deceleration affects the comfort of passengers as well.”
Sakanoue said the train’s improved tilting system allows it to “(take) curves better.”
In addition, the new system allows the Shinkansen to recognize the location and sharpness of approaching curves. Once on a curve, the train tilts toward the inside through the use of expandable air shocks, thereby reducing the centrifugal force.
The speed limit for Shinkansen on the Tokaido Line is 255 kph on curves. That will increase to 270 kph when the new schedule takes effect.
The braking force on the N700A Series, which was introduced in February 2013, is 15 percent more efficient compared with the N700 Series. The newest model is also equipped with “earthquake brakes” for abrupt stops in disaster-related emergencies.
The first Shinkansen, the 0 Series, made its debut in October 1964 shortly before the Tokyo Olympics. It had a maximum speed of 210 kph. Its successor, the 100 Series, operated at a maximum speed of 220 kph.
The 1992 introduction of the 300 Series, the first bullet train whose hulls were made of aluminum instead of steel, raised the maximum speed to 270 kph. It was also the first train used for the Nozomi super-rapid service that makes only four stops between Tokyo and Shin-Osaka stations.