With top Shinkansen speed limits reached, smoothing out the curves is the next best way to shave travel time. `There is room to upgrade Shinkansen functions, and we will continue efforts to shorten the travel time.' MASAYUKI MATSUMOTO JR Tokai president

This is the second of two stories marking the 40th anniversary of the introduction of Shinkansen bullet trains in October 1964. The Asahi Shimbun

The figures speak for themselves.

In the past 40 years, Tokaido Shinkansen bullet trains have carried a lot of satisfied customers--about 4.1 billion.

Those trains have covered a lot of ground-a total 1.5 billion kilometers, roughly 10 times the distance between the Earth and the sun.

And not a single rider has died in a Shinkansen accident.

What's even more remarkable is that the line has never shut for a full day to conduct repairs or inspections. Regular maintenance is done during off-peak hours or at night to reduce disruptions.

The network's operators continue to work to upgrade safety, speed and punctuality, the hallmark of Shinkansen service.

Central Japan Railway Co. (JR Tokai) is introducing a state-of-the-art automatic train control system designed to smooth out the bumps in braking in the next-generation N700 series Shinkansen, slated to debut in spring 2007.

For instance, the system can detect the exact start of a curve, automatically adjusting the tilt of the cars degree by degree with a special air-spring device. The train can thus navigate a relatively sharp curve without having to reduce speed, according to JR Tokai data.

For now, its designers say, the Shinkansen's fastest limit of 270 kph has been reached. So cutting time lost by slowing down for curves is the next goal. About 30 percent of the Tokaido Shinkansen route has such curves.

The new system is expected to reduce travel time between Tokyo and Shin-Osaka stations by five minutes.

Still, ``There is room to upgrade Shinkansen functions, and we will continue efforts to shorten the travel time,'' said JR Tokai President Masayuki Matsumoto.

Although Shinkansen services have never been suspended for maintenance for an entire day, that could happen in the future.

Blame it on aging, overused infrastructure.

The Ministry of Land, Infrastructure and Transport in 2002 revealed that, according to a JR Tokai report, main portions of bridges supporting Shinkansen lines are in danger of developing cracks.

JR Tokai has begun budgeting funds for imminent major repairs, expected to cost around 1 trillion yen over 10 years.

The planned repairs, set to begin in fiscal 2018, will refurbish bridges along the Tokaido Shinkansen route, lining tunnel walls and the undersides of concrete bridges with metal sheets.

It will be the first such comprehensive repair plan to be conducted since the Tokaido Shinkansen opened.

JR Tokai hopes to keep disruption to schedules from such repairs as short as possible.

``There are ways to replace an entire section of a bridge, including the pillars, by removing the old section and sliding in a new prefabricated one,'' said one official in the company's technology planning department.

Also, attempts to extend the life of existing facilities are ongoing. A recent example is the protective resin coating on bridge pillars between Nagoya and Gifu-Hashima stations. The coating is expected to prevent alkaline concrete from crumbling from long-term contact with carbon dioxide in the air, which leads to rusting of metal supports inside the concrete.

Resin coating started in 2000 and is expected to be applied to about 150 km of concrete bridge portions over the next decade.

Another Shinkansen record is its claim that not one person has died in a bullet train accident.

But the collapse of a portion of a bridge along the Sanyo Shinkansen line in the 1995 Great Hanshin Earthquake was a spectacular reminder of the line's vulnerability.

It is only too clear what tragedy would result if a full bullet train carrying 1,300 passengers ran into a collapsed portion of a bridge.

Junji Kiyono, an associate professor of earthquake engineering at Kyoto University, last year made public his scenario about such a disaster, supposing a bullet train traveling at 150 kph careened off the tracks because of a fallen bridge.

The first car would drop into the empty space. The second car would smash head-on into the other side of the severed bridge girder.

The third and fourth cars would tumble, and subsequent cars would crash into each other.

Most of the passengers would be killed, Kiyono estimated.

JR Tokai is in the process of fortifying the pillars of Shinkansen bridges, taking into account anticipated sways from temblors like the disastrous Great Hanshin Earthquake that struck Kobe in January 1995. The repair work is to be completed in fiscal 2008.

But the possibility remains that temblors greater than the 1995 quake--and terror attacks similar to the railway bomb attacks in Madrid in March this year--could strike any time.(IHT/Asahi: October 16,2004) (10/16)