Quarterly Report of RTRI
Online ISSN : 1880-1765
Print ISSN : 0033-9008
ISSN-L : 0033-9008
Volume 62, Issue 3
Displaying 1-12 of 12 articles from this issue
PERSPECTIVES
  • Hitoshi HASEGAWA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 155-158
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    The Railway Technical Research Institute (RTRI) has developed a master plan for the fiscal year 2020 and beyond, as a roadmap guiding RTRI towards the realization of its vision: "We will develop innovative technologies to enhance the rail mode so that railway can contribute to the creation of a happier society." As a matter of course, we also carry out R&D in the vehicle field according to the master plan. This journal carries the six latest research and development results in vehicle fields. In addition, this report outlines four other research results.

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  • Hiroshi UEDA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 159-162
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    Since the materials for the railway system are required to maintain the designated performance over a predetermined period of time, it is necessary to deal well with the changes over time of the used materials. On the basis of this background, our current researches mainly consist of long-time service life materials such as concrete or steel structures, and friction members such as rail, wheel, bearing, brake shoe, contact wire, pantograph contact strip. We are also developing new materials or new technologies represented by superconducting power feeding cable. This paper shows the outline of our recent research and development activities in materials technology.

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  • Ken NAGASHIMA, Takashi SASAKAWA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 163-166
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    This paper presents recent findings from RTRI regarding the development of fundamental technologies for maglev (magnetic levitation) and the application of maglev technology to the conventional railway system. This paper also introduces the latest developments regarding the future use of maglev, information reported at WCRR2019, and related news from and outside Japan.

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PAPERS
  • Shin-ichi NAKAZAWA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 167-172
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    Brake control systems used in current railways are generally open-loop structures. Braking performance can be affected by problems such as wheel slipping or the characteristics of friction components included in brake equipment. In order to automatically stabilize braking performance, we propose a new closed-loop system which can make train deceleration follow a set of target values which change with braking distance. We carried out running tests using rolling stock equipped with the proposed method. The results of the test showed that the method can contribute to reducing an increase in braking distance when there is temporary degradation in the brake.

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  • Yasutaka MAKI, Yoshiaki TERUMICHI, Masataka YAMAMOTO, Katsuyoshi IKEUC ...
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 173-178
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    It is very important to evaluate the effect of wheel flats on the acceleration of axle boxes. To understand the mechanism of the collision of the rotating wheel with a roller rig after losing contact with the roller rig, firstly, we conducted bench tests using a roller rig with a bogie set which had a wheel flat. A dynamic simulation model was then built and verified by comparing simulation and experimental results. This paper reports on how the shape at the edge of the wheel flat affects the vertical acceleration of axle boxes.

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  • Takayuki NAKAMURA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 179-184
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    Technological progress continues to advance, particularly in the field of active components such as semiconductors. This progress has enabled us to reduce the size and weight of traction inverters for railway vehicles. On the other hand, problems remain with passive components such as reactors. In particular, onboard reactors are required to be considered not only as reactor units but also as part of a whole trainset. Therefore, as a determining factor, it is essential for reactors to be small and light. This paper focuses on problems such as flux leakage and resonance, which are unintentionally caused by onboard reactors, and explains changes in inductance values of reactors, so that this investigation informs further investigations.

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  • Tomohiro OKINO, Keisuke NAGATA, Kazuma NAKAI, Hidetoshi KOBAYASHI
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 185-190
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    While standards for crashworthiness of railway vehicles have been defined in Europe and the U.S., there is no standard in Japan. Therefore, it is important to establish an evaluation method for crashworthiness of railway vehicles in Japan. The authors carried out finite element analyses under various conditions based on the statistical analysis of serious level-crossing accidents. We evaluated the mean decelerations (conforming to European standard), the maximum decelerations (U.S. standard) and integrated values of the deceleration, which are obtained from impact deceleration waveforms in the passenger area. We also performed finite element analyses of dummy's behavior and injury values using these deceleration waveforms as input. We examined the correlation between these evaluation results and dummy's injury values. As a result, we confirmed that the integrated values of the deceleration of the passenger area had the highest correlation with the dummy's injury values.

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  • Sho YAMANAKA, Tadashi TOYOHARA, Mikiya ITO
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 191-196
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    Fires occurring on railway rolling stock may not only potentially injure passengers and crew but also damage the rolling stock equipment. It is important to evaluate the performance of materials against fire. Heretofore, the time-dependent production of smoke and toxic gases relating to combustion behavior has not been considered. Quantitative understanding of combustion behavior is important, for example heat release rates, smoke production and gas generation. In the light of this context, the authors designed and fabricated a new combustion test device that can simultaneously measure time-dependent changes of combustion phenomena through combustion tests on materials for railway rolling stock. The combustion performances of materials for railway rolling stock were evaluated based on these results.

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  • Kazuyuki HANDA, Katsuyoshi IKEUCHI, Shinichi SAGA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 197-200
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    This paper describes the development of a wheel friction block that integrates the functions of wheel flange lubrication and tread adhesion improvement. We devised a configuration in which friction material with adhesion increasing material on the tread and material containing solid lubricant with MoS2 at the flange are applied vertically by a tread cleaning device. The developed blocks were tested for an express train in operation and traveled about 200,000 km. As a result, the wear rate of the wheel flanges was reduced by an average of about 40% compared to the wheel flanges of vehicles not equipped with the developed blocks.

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  • Tomoyuki AKASAKA, Yusuke FUKUMOTO, Atsushi ISHIHARA, Kenji SUZUKI, Yus ...
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 201-206
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    Superconducting feeder cables shrink because of thermal stress during the cooling process. When a long superconducting feeder cable is laid along a railway line, measures must be taken to prevent cable shrinkage. This paper therefore introduces a method which was used to lay a 300-m class superconducting feeder cable along a test track. This paper also reports that the method is suitable for similar cables, because no buckling or rupture points were observed after X-ray radiographs were taken over the whole length of the cable after its installation, and that transmission tests were conducted successfully with the cable.

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  • Katsutoshi MIZUNO, Masafumi OGATA, Minoru TANAKA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 207-212
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    In electromagnetic vibration tests, a ground coil is excited under the strong magnetic field of a superconducting magnet. Since the vibration mechanisms in the test are the same as for actual maglev (magnetic levitation) running conditions, electromagnetic vibration tests are therefore an important durability test for ground coils. We carried out electromagnetic vibration tests with a superconducting magnet with REBCO wire, which is a high-temperature material. This paper also proposes a novel monitoring and protection method for REBCO magnets.

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  • Yasuaki SAKAMOTO, Keigo UKITA, Takashi SASAKAWA
    Article type: research-article
    2021 Volume 62 Issue 3 Pages 213-219
    Published: August 01, 2021
    Released on J-STAGE: August 26, 2021
    JOURNAL FREE ACCESS

    Studies have been carried out on a rail brake applying linear induction motor technology. This brake is capable of generating contactless braking force. In addition to the contactless braking, no on-board power supply for energizing this brake is required by using dynamic braking. In order to place this brake into service however a self-diagnosis method for checking the soundness of the device is necessary. Therefore, a condition monitoring method for this brake using an excitation inverter, not using dedicated sensors, was considered and examined on a test bench with a roller rig. Results from these tests clarified that the devised method is useful for self-diagnosis.

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