New tech lightens, quickens shinkansen trains

by Keiichiro Otsuka

Kyodo News

New bullet trains on the Tokaido and Sanyo Shinkansen lines employ state-of-the-art high speed and lightweight technology to speed passengers along the 1,174.9-km route between Tokyo and Hakata, Fukuoka Prefecture.

The new N700 series coaches, introduced in July, are replete with cutting-edge materials and parts that make them lighter, allowing them to run faster and give a more comfortable ride to passengers than other trains.

The latest bullet trains are capable of traveling the 552 km between Tokyo and Shin-Osaka in two hours and 25 minutes at top speed, trimming five minutes from the time required by other shinkansen.

The travel time between the two stations was three hours and 10 minutes when bullet trains were inaugurated in 1964, the year Japan hosted Asia’s first Summer Olympics.

The five-minute reduction is made possible by the newest and most advanced technology — a tilting system that allows the trains to negotiate curves at high speed. The system provides not only an improvement in speed but a more comfortable ride.

Air springs, each measuring about 66 cm in diameter and weighing about 44 kg, comprise the key part of the system. The parts are manufactured by Sumitomo Electric Industries Ltd. of Osaka and other firms.

When the N700 series coaches approach a curve, air directed by the system raises the height of the springs on the outer side by several centimeters, tilting the coach 1 degree from horizontal.

The weight of the springs in the N700 series is about 10 percent lighter than those used in coaches of the 700 series, which has been the shinkansen mainstay. The N700 series, with N standing for new or next, has been jointly developed by Central Japan Railway Co. (JR Tokai) and West Japan Railway Co.

Some N700 coaches are already operating on Nozomi trains — the fastest category — but JR Tokai and JR West plan to expand their use to 96 trains by the end of fiscal 2011 to replace the Nozomi.

The new cars are about 8 tons lighter than those of the 700 series, saving energy, and a special polycarbonate developed by Teijin Chemicals Ltd. of Tokyo has been adopted for windows instead of the double glazing installed in ordinary class coaches.

The windows, 50 cm wide and 52 cm high, are smaller than the windows in the 700 series. In terms of unit area, an N700 car weighs about 30 percent less than a 700 series carriage. Officials said air resistance has been reduced because the new windows do not have a protruding edge.

Polycarbonates are strong and unbreakable but vulnerable to scratches.

Teijin Chemicals enhanced durability by applying a special coating to the surface of the windows. It also developed a new technique to minimize distortion when viewing out that employs an injection molding machine to make windows from resin poured into a metal mold.

Polyester cushions made by Teijin Fibers Ltd. of Osaka are used in the passenger seats. Urethane was previously used, but polyester is considered more resilient and durable, and generates only small amounts of harmful gases in the event of fire.

Teijin Fibers is expected to deliver polyester material for more than 60,000 passenger seats to JR Tokai and JR West.

Manufacturers supplying parts and materials to the railways have complained they are unable to make a profit due to costs. They are hoping to tap into new markets in other areas, including automobiles and airplanes, in the future.

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