Quarterly Report of RTRI
Online ISSN : 1880-1765
Print ISSN : 0033-9008
ISSN-L : 0033-9008
最新号
選択された号の論文の12件中1~12を表示しています
PERSPECTIVES
PAPERS
  • Gaku MORITA, Tomoyuki HIKOSAKA, Hirokazu HAYASHIDA, Masashi KATO
    2019 年 60 巻 1 号 p. 14-21
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    This paper describes a new voltage adjustment technique and its design method. In the new design, a voltage compensator, comprising a variable inductor and a controller, is connected with a transformer and a rectifier on either side in series. The authors developed a new configuration of the variable inductor suited for railway application, with a focus on six-phase AC and large current capacity. A fast simulation method for designing the inductor was developed based on the magnetic flux circuit theory and the non-linear simulation technique for ferromagnetic materials.

  • Chikara YAMASHITA, Takuya OHARA, Shigeyuki KOBAYASHI
    2019 年 60 巻 1 号 p. 22-27
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    Electrical connections between the contact wire and the messenger wire are always subject to fatigue damage due to vibration caused by the passage of pantographs. Therefore, it is necessary to clarify the fatigue mechanisms affecting electrical connections to propose measures to mitigate damage. In this paper, the authors focus on the resonance of the electrical connection with catenary system and relative vibration displacement between the contact wire and the messenger wire considering them as major fatigue factors. As a result of OCL-pantograph simulation, the authors clarified the conditions under which fatigue damage of the electrical connection can occur. In addition, the authors proposed a new electrical connection which has a fatigue life exceeding 10 million vibration cycles.

  • Takamasa HAYASAKA, Tadanori USUKI
    2019 年 60 巻 1 号 p. 28-32
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    Battery-powered electric trains charge their batteries through collection of a large current from contact wires through their pantographs whilst at a standstill in stations. This current tends to be larger than that collected by normal trains when immobile in a station. Usually, current flowing through a contact wire causes an increase in the temperature of the contact wire. In the case of battery-powered electric trains, pantograph contact strips do not slide along the contact wire in non-electrified sections, allowing an oxide-like film to form on the contact wire depending on the number of days of exposure. The influence of this film on current collection is thought to be high, though this has not yet been evidenced. Consequently, the authors of this paper conducted exposure tests, measuring the thickness of the film on contact wires, contact-resistance, and numerically simulating thermal conduction, to unravel the unknowns surrounding influence of this film. This paper reveals the influence of the film and proposes a method and cycle for maintenance in the light of these experiment results.

  • Masato UKAI
    2019 年 60 巻 1 号 p. 33-39
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    Existing image processing programs for detecting structural damage such as cracks have required the fine-tuning of numerous parameters and experience-based expertise. A method for distinguishing different types of cracks applying deep learning has been developed using tunnel lining images. A classifier was created after learning from a large volume of images in two groups - either with "presence of a crack" or "absence of a crack." The classifier successfully recognized the presence or absence of cracks in images at a rate of more than 90%. Using a color-coded pixelated image to show the position of probable cracks, this paper proposes a hybrid detection method for analyzing cracks with a focus on their location and direction of progress.

  • Takashi TOYAMA, Nozomi NAGAMINE, Tatsuya OMORI, Kenichi KITAO, Ryuta N ...
    2019 年 60 巻 1 号 p. 40-45
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    Periodic measurement of the structure gauge is essential to ensure safe train operation. Measuring the clearance gauge however, is time and labor intensive given the vast number of trackside facilities. An inexpensive and efficient measuring device using laser range scanners was therefore developed. A management system is also being developed, which maps measured three-dimensional point cloud data to facility data. This paper describes the problems and solutions related to applying the laser range scanners for structural gauging, and presents results obtained from experiments. This paper also describes progress achieved in the development of the management system.

  • Yoichi SUGIYAMA, Koji IWATA, Haruo YAMAMOTO
    2019 年 60 巻 1 号 p. 46-51
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    We propose a train operation control system for drawing up operation curves composed of pairs of precise train position and precise operation time, and controlling trains and ground facilities according to the plan. This system realizes more flexible control than that of the conventional system by controlling the on-board device and the ground device according to the train performance curve from the central device, where the management of operations function and the safety control function are integrated. In this report, we describe the control method based on "band" with a margin for safety added to the operation curve, and the requirements for securing safety. In addition, we have confirmed by the simulator that there is no bottleneck in the transmission path, even though the information concentrates on the central device.

  • Mitsugi SUZUKI, Hisayo DOI, Daichi NAKAJIMA, Takayuki TANAKA, Takatosh ...
    2019 年 60 巻 1 号 p. 52-57
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    When vehicles run through curved sections presenting significant twisting irregularities, the wheel load on the front axle on the outer rail may decrease. Concomitant large lateral force in such cases make it easy for the wheel to climb the rail, increasing the risk of derailment. A new type of bogie has therefore been developed to prevent flange climb derailment by controlling the decrease in wheel load. Confirmation was obtained of the satisfactory basic performance of the bogie through a series of experiments. Confirmation was also obtained of the satisfactory performance of the bogie in the operational running speed range through experiments carried out on the RTRI test line.

  • Kohei MUROTANI
    2019 年 60 巻 1 号 p. 58-64
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    The coastal area in the Tohoku region of Japan suffered serious damage from the tsunami caused by the Great East Japan Earthquake in 2011. The purpose of this research is to develop a simulator in order to predict potential damage and put in place disaster prevention measures to protect railway structures against such large scale tsunamis. For this research, a simulation was made of the tsunami generated by the Great East Japan Earthquake to evaluate the damage process that occurred at Shishiorikarakuwa station in Kesennuma city. The tsunami simulator involves a three stage zoom analysis covering a large area from the epicenter to the urban area. The results of the tsunami simulation were then used to conduct a structural analysis of the Shishiorikarakuwa station subject to the tsunami fluid pressure.

  • Daisuke YAMAMOTO
    2019 年 60 巻 1 号 p. 65-71
    発行日: 2019/02/01
    公開日: 2019/02/24
    ジャーナル フリー

    Estimation of vehicle dynamic characteristics depends on sufficiently accurate locating of the wheel/rail contact point. However, since it is not possible to place a camera on a truck close enough to the rail head level, locating the wheel/rail contact point while a vehicle is running was not possible in previous studies. To solve this problem, this study proposes a new method for digitalizing the contact point based on the method presented in the study by Burstow et al., which uses thermal imaging. An experiment to locate the contact position was carried out using an actual vehicle on the RTRI test line. The test results confirmed that the contact position between the wheel and the rail could be identified accurately while the vehicle was running in conditions suitable for using a thermography camera. In addition, this paper describes how this proposal could be applied to a derailment experiment.

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