Quarterly Report of RTRI
Online ISSN : 1880-1765
Print ISSN : 0033-9008
ISSN-L : 0033-9008
Volume 47, Issue 1
Displaying 1-10 of 10 articles from this issue
PAPERS
  • Hiroshi SEINO, Shigeki MIYAMOTO
    2006 Volume 47 Issue 1 Pages 1-5
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    Running tests of the Superconducting Maglev (JR-Maglev) have been carried out on the Yamanashi Maglev Test Line (YMTL) since April 1997. In the end of fiscal 2004, the cumulative running distance reached 434,066 km with several bogies and car-bodies exceeding 200,000 km, the initially set distance for durability evaluation. In March 2005, the results of running tests over the eight years, technical developments and several durability verification bench tests were evaluated by the Maglev Practical Technology Evaluation Committee that the key technologies necessary for the future revenue service were extensively established. This paper provides an outline of the developments and running tests in past five years together with detailed results from the YMTL running tests in fiscal years 2003 and 2004. In addition, the results of long-term durability tests during the eight years are summarized.
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  • Masateru IKEHATA, Tamami KAWASAKI, Yuji SUZUKI, Hidesuke SHIMIZU, Taka ...
    2006 Volume 47 Issue 1 Pages 6-11
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    We investigated the biological effects of the magnetic field produced in the superconducting Maglev system environment, such as the extremely low frequency intermittent pulsed magnetic field (LFIP-MF) that is generated along the guideway when a Maglev train passes. We observed no evidence of any biological effects from exposure to the Maglev system's LFIP-MF in "in vivo" long-term exposure experiments using AKR/JSea mice, in "in vitro" short-term exposure experiments as bacterial mutation assay, a yeast mutation assay or an analysis of global gene expression profiles in yeast. These results suggest that the Maglev system's environmental LFIP-MF does not have any health/biological effects that would need to be considered as part of an environmental assessment.
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  • Masaru IWAMATSU, Masafumi OGATA, Hiroshi SEINO, Toshiki HERAI, Tetsuro ...
    2006 Volume 47 Issue 1 Pages 12-17
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    For the superconducting Maglev system to be commercially viable, it is important to reduce costs. Simplifying the ground coil structure effectively would achieve this, but will increase the harmonic magnetic fields that intensify the vibration of on-board superconducting magnets (SCMs). Excessive vibration gives rise to greater heat loss. We have studied an SCM for simplified ground coils and with this paper report on its design, the results of emplacement tests and provide several analyses.
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  • Yasuaki SAKAMOTO, Takayuki KASHIWAGI, Erimitsu SUZUKI, Katsuya YAMAMOT ...
    2006 Volume 47 Issue 1 Pages 18-23
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    One of the most important subjects in the superconducting Maglev system is a method for providing onboard service power. As a solution, a linear generator is being developed that can collect power without contact by utilizing the harmonic magnetic field around the ground coils and generate an electromagnetic force between them and the superconducting magnets by controlling the current in the generator coils. By using this controllable electromagnetic force, it becomes possible to add magnetic damping to the electrodynamic levitation system with a small damping force. This paper describes the results of the running tests of the linear generator using zero-phase current control, combined with the magnetic damping function.
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  • Hiroshi HATA, Hiroki KAMIJO, Hiroyuki FUJIMOTO, Ken NAGASHIMA, Kazuya ...
    2006 Volume 47 Issue 1 Pages 24-27
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    Having undertaken studies into a lightweight and highly efficient superconducting transformer for rolling stock, we developed a prototype with a primary winding, four secondary windings and a tertiary winding using bismuth (Bi-2223) high temperature superconducting wire. Its primary voltage is 25kV, which is widely adopted as the catenary voltage on the world's high-speed lines. We adopted liquid nitrogen cooling, the weight being 1.71t excluding the refrigerator. The maximum output available to maintain superconductivity is 3.5MVA. This paper describes the transformer details and test results.
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  • Kiyoshi SATO, Minoru SASAKURA, Katsunori AKUTSU, Toshikazu SATO, Yutak ...
    2006 Volume 47 Issue 1 Pages 28-33
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    Noise generated on existing narrow-gauge railway lines is composed of rolling noise and noise generated from traction drive unit. In recent years, adequate measures have been needed to cope with rolling noise due to speedup operations and the noise emitted from electric apparatus and traction drive unit.
    This paper reports on the characteristics of vibratory noise radiated from wheels as obtained from running / bench tests of the wheels with different web shapes, and those with corrugated webs and straight standard type, all of which have been currently used.
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  • Hiro-o YAMAZAKI, Masao NAGAI, Takayoshi KAMADA
    2006 Volume 47 Issue 1 Pages 34-38
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    In order to operate trains efficiently at high speeds regardless of their length, control systems that can provide stable braking forces must be developed. In the designing brake control systems, it is essential to consider the robustness because there are model uncertainties that result from nonlinear characteristics for adhesion and the brake material friction coefficient. This paper presents an innovative new wheel slip prevention control system that utilizes sliding mode control. Simulations for the proposed wheel slip prevention control system are performed and compared with some conventional control laws. The results of simulation prove the effectiveness of the proposed control system as compared with conventional types, and show the high brake performance under non-linearity of brake dynamics.
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  • Shunichi KUSUMI, Takahiro FUKUTANI, Kazuyoshi NEZU
    2006 Volume 47 Issue 1 Pages 39-45
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    Large contact force fluctuations between contact wires and pantographs cause unstable current collection conditions and so it is important to measure and estimate the contact force to obtain a better knowledge of current collection quality. Contact force waveforms are affected by the condition of equipment used on overhead contact lines, so it is to be expected that the contact force waveform represents the state of repair of an overhead contact line. This paper describes contact force waveform characteristics against the static height of Shinkansen contact wires and their application in overhead line diagnosis.
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  • Chikara YAMASHITA, Atsushi SUGAHARA
    2006 Volume 47 Issue 1 Pages 46-51
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    When a pantograph passes underneath a contact wire, the upward force causes a bending stress in the contact wire. If this stress is high and occurs frequently, there is a possibility that the contact wire will suffer a fatigue fracture. To estimate the fatigue life of a contact wire, we have been using the S-N curve prepared for a mean stress of 88.2 MPa. In addition, a contact wire is gradually worn down by running contact strips so that the mean stress governing its fatigue life gradually increases. To estimate the fatigue life of a worn contact wire correctly, therefore, the influence of the mean stress on contact wire fatigue needs to be examined. For this paper, we carried out fatigue tests on GT110 harddrawn copper contact wire at a mean stress of 154.2 MPa to obtain another S-N curve. Then, by using parameters that included the mean stress, we prepared a fatigue curve that integrates S-N curves for any mean stress. Finally, we estimated contact wire fatigue damage using this fatigue curve and proposed a new method to establish the allowable bending strain amplitude.
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  • Masatoshi SHIMIZU, Satoshi HARADA, Akinori OYA, Koichiro TOKUDA
    2006 Volume 47 Issue 1 Pages 52-58
    Published: 2006
    Released on J-STAGE: May 25, 2006
    JOURNAL FREE ACCESS
    Because of their simple structure and low-maintenance characteristics, railways in Japan have often adopted overhead rigid conductor lines for current collection systems applicable to underground track sections or tunnels. With regard to the copper Type T rigid conductor line adopted on some JR commercial lines, undulating wear appeared at intervals of about 60 mm on contact wire sliding surfaces. Such wear would cause impaired train speedup and thus increase maintenance costs. We investigated the causes of the wears, and proposed measures to improve the quality of overhead rigid conductor lines.
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