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[Kahaner:26] Bullet-train technology - fun to read 1 of 2
From: David Farber <farber () central cis upenn edu>
Date: Wed, 28 Dec 1994 03:25:41 -0500
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
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