[Kahaner:26] Bullet-train technology - fun to read 1 of 2

[David Farber <farber () central cis upenn edu>]

From:
 Dr. David K. Kahaner
 US Office of Naval Research Asia
 (From outside US):  23-17, 7-chome, Roppongi, Minato-ku, Tokyo 106 Japan
 (From within  US):  Unit 45002, APO AP 96337-0007
  Tel: +81 3 3401-8924, Fax: +81 3 3403-9670
  Email: kahaner () cs titech ac jp
Re: Japanese Bullet train technology.
12/27/94 (MM/DD/YY)
This file is named "train.94"


ABSTRACT. Summary of main technical issues associated with Japanese
"bullet" trains, (Shinkansen). This system is celebrating its 30th
anniversary in 1994, carries up to 130 million passengers annually
(3 billion in total), runs nearly 300 trains per day on the main line
from Tokyo through Osaka, has never had a derailment or collision
accident, and maintains a zero mortality rate for passengers and crew.


Japan's Shinkansen, bullet trains, are remarked on by all visitors, for
their speed and reliability as well as their frequency. There are three
routes, Tokaido (the first, and most heavily travelled, along the waist
of Japan from Tokyo through Osaka and Hiroshima, ending in Hakata on the
island of Kyushu) running west, Tohoku (from Tokyo to Sendai and
Morioka) running north east, and Joetsu (from Tokyo to Niigata on the
Japan Sea) running almost due north. The article below describes several
key technologies associated with this system, especially the car
construction and driving systems which are designed and manufactured at
Hitachi's Kasado Works (factory). System integration, scheduling and
related topics are not discussed.


This article appeared in JETRO's (Japan External Trade Organization) New
Technology Japan, Vol 22, No 9, Dec 1994. Several figures and photos in
the original article have been omitted here.  This periodical is an
official Japanese government sponsored publication, providing
descriptions of various Japanese technologies, it is not a technical or
refereed journal. For further information contact the addresses listed
in the article or the following.


      JETRO, Machinery & Technology Dept
      2-5, Toranomon 2-chome, Minato-ku, Tokyo 105 Japan
       Tel: +81 3 3582-4631; Fax: +81 3 3582-7508
or
      Three "I" Publications
      5-16, Uchikanda 1-chome, Chiyoda-ku, Tokyo 101 Japan
       Tel: +81 3 5280-3100; Fax: +81 3 5280-2625








"NOZOMI" SHINKANSEN TRAIN MANUFACTURING AT KASADO WORKS, HITACHI LTD


The SHINKANSEN train "Nozomi," a symbol of Japan's advanced bullet train
technologies, was commissioned into service by Central Japan Railway Co.
on March 8, 1993. The "Nozomi" train has a running speed of 270 km/hr
and travels between Tokyo and Osaka in two and a half hours. And the
success of "Nozomi," both in commercial and technical aspects, has been
a positive addition to the 30th anniversary of Japan's Shinkansen train
operation. By October 1994, the Shinkansen had transported more than 3
billion passengers during the 30 years since the first Tokaido
Shinkansen bullet train started commercial operation in October 1964.


This article introduces the Kasado Works of Hitachi, Ltd. which is
presently assembling the "Nozomi." Hitachi participated in the
development of "Nozomi" from the initial stage and contributed to the
successful development with its accumulated expertise in both mechanical
and electric machinery technology. From the beginning of the Shinkansen,
the Kasado Works has been involved in the development and manufacture of
Shinkansen trains and about one-third of all Shinkansen vehicles
produced until now have been manufactured at this works of Hitachi.


NEW FRONTIER OF RAILWAY TRANSPORTATION


The construction of Shinkansen Line was a highly remarkable achievement
involving tremendous efforts, although at first glance it may appear as
if the development and progress of the Shinkansen has been achieved
without much trouble in the wake of the country's high economic growth.
When the Shinkansen construction project was launched, however, the
internationally prevailing consensus was that railway transportation was
destined to tread the path of gradual demise.  What actually happened to
the railway in the United States seems to have proved the prediction had
some validity. Those widespread negative opinions were based on the
assumption that railway transportation cannot achieve an operational
speed exceeding 160 km/hr, so the railway would hardly be capable of
competing with airlines in the aspects of speed of travel and were being
overtaken by the convenience of the automobile that was rapidly being
popularized.


Despite this prevailing negative outlook, innovative-minded experts of
Japan National Railway (JNR) believed that the railway can compete with
aircraft in travel time considering the access time to the airport and
the waiting time for scheduled flight services, assuming that commercial
running speed of railways could be increased to 200 km/hr by advancing
existing railway technologies. JNR was also in an urgent need of
capacity expansion of the Tokaido line railway service-the main artery
for the Japanese economy-as it was heavily over-congested at that time.
They believed that the construction of new Tokaido Line, Shinkansen, was
commercially viable and socially needed.


After surmounting various obstacles, the Tokaido Shinkansen Line became
a reality and started operation at the revolutionary high speed of 200
km/hr. As a result, it is today indispensable for the Japanese social
and business activities, transporting an average of 350,000 passengers
daily and as many as 130 million passengers annually. This has been made
possible not only through the high-speed of individual trains but also
through the established total operation system which assures safe and
highly congested train operation.


HIGH SPEED ELECTRIC CAR SYSTEM


The Shinkansen trains consists of electrically powered cars--that means
basically all individual cars are equipped with electric motor driving
systems. This is in contrast to locomotive trains in which the
locomotive pulls the passenger coaches. The realization of the
high-speed Shinkansen with the electric train system had a great
significance. The French "Train a Grande Vitesse (TGV)" runs on a
centralized power system, in which the heavyweight, high-output
locomotives at both ends pull the passenger coaches via the friction
between the vehicle's wheels and rails. It is a system suitable to
European railways which run basically on straight tracks in wide plains
with solid foundations, but unsuitable in Japan where the ground is
flimsy and the tracks full of curves and undulations and inter-city
distances are short, making it necessary for the trains to accelerate
and decelerate frequently. One of the advantages of the electric car
system is that the motor functions as a brake to reduce the speed of the
train. When the power feed to the electric car motors is stopped, the
wheels continue revolving, keeping the motors rotating, resulting in
electricity generation by magnetic induction. As the force acts in the
direction opposite to the axle's motion it functions as a brake to the
train. All the motors equipped on each coach can be utilized effectively
to reduce the speed, making the electric train system advantageous on
Japanese railways which involve frequent deceleration and acceleration.
In addition, by virtue of the remarkable progress achieved recently in
semiconductor technologies, the electric train system has undergone
tremendous improvements in power, operability and safety administration,
so the system is becoming increasingly advantageous.


The most notable contribution of Japanese Shinkansen to the
international community is that it fully proved the economical viability
of railways through the achievement of mass-transportation system at
high-speed. The conditions unique to Japan, such as the dense population
and the concentration of economic activities in limited number of large
urban cities, may have prompted the Shinkansen project, but today the
necessity of mass transportation systems at high-speeds is realized
throughout the world and the vital importance of railway transportation
is recognized. As a result, new railway construction projects such as
the high-speed railway networks in Europe-the French Railway's TGV
system and the German Railway's Inter-City Express (ICE) system-are
being implemented. Also, due to the unceasing mass production of
automobiles, the limitations of automobile/highway network
transportation are being recognized in the environs of large cities due
to the deterioration of efficiency because of the inevitable heavy
traffic congestion. This is another major factor that is implementing a
reappraisal of the railway transportation worldwide.


HIGH SPEED WITH SAFETY


The viability of railway systems has been based on high-speed
transportation technology, and Japan's Shinkansen Line has taken the
lead in this respect. The Shinkansen trains, ever since they were
commissioned into service in 1964, have run for an aggregate distance of
1 billion kilometers, and while transporting over 3 billion passengers
at a speed of over 200 km/hr (currently operating 282 trains per day on
Tokaido Shinkansen alone) has had no derailment or collision accident
whatsoever, and has therefore established the highest level of safety
and reliability with no mortality whatsoever to passengers or crew
members.


Although the Shinkansen has been surpassed by the TGV in its maximum
speed, it is still highly praise-worthy in that it has realized
high-speed operation while constrained by Japan's geographical
conditions, which require operating on tracks with many curves built on
unsolid ground, while also coping with environmental problems such as
noise suppression due to densely populated regions. The overall
technologies which make the operation of the Shinkansen lines in Japan
possible despite these constraints -- advanced power electronics
technologies, vehicle weight reduction, energy conservation and safety
assurance -- may be regarded as the world's most advanced technologies.


THEMES RESOLVED FOR THE REALIZATION OF "NOZOMI"


[The original Shinkansen trains run at 200 km/hr. A newer "Hikari"
operates at 220 km/hr, and the current "Nozomi" operates at 270 km/hr.
See below for plans to put into service (1997) a 300 km/hr train.]


The commercial operation running speed of 220 km/hr of the "Hikari" is,
in itself, an astounding speed, therefore the realization of higher
speed of 270 km/hr for "Nozomi" required innovative solution of many
technical themes. The main constraining factors to be solved were as
follows:


 * Constraint No. 1: Numerous curves
One of the biggest obstacles hampering speedup and shortening of travel
time was the existence of many curves on the line. About two-fifths of
the approximately 500km Tokaido Shinkansen Line between Tokyo and Osaka
consists of curves, and the sharpest curves with a curvature radius of
2,500m (R2,500) include about one-eighth of the total line length.
These curves would hardly be problematical in conventional lines with
lower speed trains, but when the running speed exceeds 200 km/hr, they
stand out as a formidable matter. Therefore, on the newer Shinkansen
lines (Sanyo Shinkansen [from Osaka to Hakata] as well as Tohoku/Joetsu
Shinkansen lines) the sharpest curves are suppressed to a radius of
4,000m.


The required shortening of travel time would have been impossible if the
maximum speed was attained only on the straight-line portions.  Even the
speed at the difficult portions of tracks consisting of sharp curves
must be raised as much as possible. If the curved tracks could be
replaced with straight tracks, the problem would be quite simple, but
the problem faced by "Nozomi" was that the travel time had to be
shortened with the existing line consisting of numerous curves.


A maximum speed of 270 km/hr had already been attained in 1985 by a
rolling stock truck in a running test on the Tohoku Shinkansen Line, in
which case no serious problem was encountered, but attaining a speed of
250 km/hr at curved sections is a different matter. With the "Nozomi,"
the main objective was to attain a travel time of 2 hrs 30 minutes,
which was regarded necessary to make the Shinkansen line service
competitive with airlines.


 * Constraint No. 2: Vibration and noise
The Tokaido Shinkansen Line runs through a route containing one city
after another. In the TGV and other railway systems in Europe which
mostly run through pastoral regions, environmental noise problems hardly
occur.  In Japan, there is a requirement to suppress the noise at points
25m from railway lines to less than 70 phons due to the need of
protecting environments for citizens.


The main sources of noises are the wheel/rail noise generated by the
wheels rolling along the rails, the noise generated between pantograph
[device on the roof of the car providing electrical connection to the
catenary] and catenary [external wire power source], the aerodynamic
noise/air-friction noise generated by the vehicle's impact with the air,
and the structural noise generated when the train passes bridges or
other structures. Among these noise sources, the wheel/rail noise,
structural noise and vibrations increase with the vehicle's weight, so
the matter of rolling stock weight reduction is the most vital issue.


Railway engineers use the term "axle load" when discussing the
influences which the vehicle weight exerts on the railway track. It is
the load that is exerted on an axle linking the left and right wheels. A
Shinkansen car is equipped with 2 sets of trucks, each with 2 axles (4
wheels), so the axle load is obtained by dividing the vehicle weight by
4. [The underbody truck mounts wheels, motors, brakes and shock
absorbers.] With the 0-series car, the weight with passengers is 64tons,
so the axle load is 16tons. Experiments showed that suppressing the axle
load of the 270-km/hr "Nozomi" train to 11.3tons would suppress the
vibration to less than that of the 100-series "Hikari." This means a
vehicle weight of 45tons.


PURSUIT OF WEIGHT REDUCTION
To attain a high speed of 270 km/hr under these constraints, the most
vital issue was weight reduction for all main vehicle components-the
body, truck and the motor together with its related electrical parts.
The following basic technologies have been the focal points:


 1) The body of 0-series and 100-series cars are made primarily of steel
structural members, but with the 200-series cars, aluminum structural
members were introduced. The "Nozomi " introduced further advanced use
of aluminum structural members.


 2) As for the truck, the large central beam (bolster) of the
conventional type truck was eliminated. A lighter body require lighter
trucks, so additional weight reduction was made possible.


 3) The motor and its related electrical equipment were changed to an AC
motor system. This enabled greater reduction in weight, and the control
equipment was made lighter.


NEW TECHNOLOGIES RELATING TO NOZOMI


 * Strong, lightweight, high-speed car body
Achieving lightness by sacrificing structural strength is not
acceptable, so adequate rigidity has to be secured while achieving
significant weight reduction. However, the increased maximum speed
demands a proportional increase in body strength. The car body must
display efficient rigidity to withstand the atmospheric changes