Photo/IllutrationCar No. 10 of the ALFA-X test train, seen here Feb. 8 in Kudamatsu, Yamaguchi Prefecture, has a characteristically long nose extending 22 meters. (Ayateru Hosozawa)

  • Photo/Illustraion

KUDAMATSU, Yamaguchi Prefecture--The nose accounts for more than 80 percent of the lead car on an experimental bullet train that is designed to set a service speed record of 360 kph.

However, East Japan Railway Co. (JR East) officials say deceleration is taking priority over acceleration in developing the next generation Shinkansen.

JR East on Feb. 8 gave media representatives a sneak peek at the car of the ALFA-X test train at Hitachi Ltd.’s Kasado Works here, one of the development centers.

The experimental train is scheduled to make a test run along the Tohoku Shinkansen Line as early as May.

One of two available types of lead cars was shown to reporters.

Car No. 10, at the end of the train facing north toward Shin-Aomori Station, has a tapering nose section that extends about 22 meters.

That is much longer than the 16-meter nose of Car No. 1 at the end facing south toward Tokyo.

The nose of the Series E5 train, the current mainstay model, is about 15 meters long.

The long nose is intended to suppress the generation of noise-inducing pressure waves when the train enters a tunnel, officials explained.

AUXILIARY BRAKES TO QUICKEN EMERGENCY STOP

Despite the public’s attention on the speed of the new Shinkansen, JR East wants to first ensure optimal braking performance for the ALFA-X, which is short for “Advanced Labs for Frontline Activity in rail experimentation.”

Running at faster speeds requires stopping more quickly.

JR East officials said the required emergency braking distance will remain at “4,000 meters or less” for the ALFA-X, despite its target service speed of 360 kph, the fastest in the world.

That distance, required for responses to earthquakes, refers to the space between the actual stop and when emergency brakes are applied at top speed.

That required distance remained the same when the Series E2 train model debuted on the Tohoku Shinkansen Line in 1997 with a maximum speed of 275 kph, and the entry of the current Series E5 model with a top speed of 320 kph.

Athough there are no corresponding legal regulations, JR East set the required distance from its development principle of “no change of the status quo for the worse,” which mandates that higher speeds should not come at the cost of reductions in other performance indicators.

Developers’ top priority is to ensure trains can stop as soon as possible to avoid derailing at high speeds in the event of an earthquake. During the Great East Japan Earthquake of March 2011, 27 commercial train services were operating on the Tohoku Shinkansen Line, but all of them came to an emergency stop, and no injuries were reported.

To meet the emergency braking distance requirement for the ALFA-X, JR East is eyeing two different auxiliary braking systems that have never been used on Japan’s railroads.

Simply strengthening the capabilities of conventional main brakes, which act on train wheels, is insufficient to attain that goal.

The developers decided to use “aerodynamic brakes,” which draw on air resistance, and “maglev-type decelerators,” which use electromagnets, as auxiliary braking systems.

An aerodynamic braking system was installed on the Fastech 360 test trains of the previous generation. Its resistance plates, which protruded to both sides of the roof, earned the moniker “cat ears.”

The system was found effective in a test of an emergency stop from an initial speed of 360 kph. But it was not adopted for the Series E5 train model because of some weaknesses, including protrusion of the housing into the train cabin.

In the ALFA-X, the resistance flaps were designed to be more compact so that more flaps can be installed on the roof. They were redesigned to stand up from a flat position so they will not interfere with the cabin space.

The maglev-type decelerators are configured to bring a coil, which is mounted on a bogie, very close to the rail when an earthquake strikes so that an electromagnetic force is generated to decelerate the train.

Germany’s Intercity-Express (ICE) high-speed rail network has adopted a similar eddy-current brake system, the officials said.

“Pursuit of further safety and stability is the topmost development concept of the ALFA-X, although the spotlight is often on its maximum speed,” said Koji Asano, director of JR East’s Advanced Railway System Development Center. “We will be working steadily on improving the performance and reliability of our braking systems.”