Quarterly Report of RTRI
Online ISSN : 1880-1765
Print ISSN : 0033-9008
ISSN-L : 0033-9008
Volume 50, Issue 1
Displaying 1-9 of 9 articles from this issue
PAPERS
  • Guoquan LI
    2009 Volume 50 Issue 1 Pages 1-7
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    The majority of the costs involved in logistics come from freight transport expenses, which are affected by various factors in today's world of economic deregulation. This study seeks to investigate the effectiveness of railway freight as a way of controlling logistics costs under the current conditions faced by major shippers. Models to express the compositive mechanism of truckload freight rates (i.e., transport expenses per ton-kilometer) based on a mileage system are introduced to enable case analysis. The suitability of each model and the availability and explanatory power of each constituent factor are then discussed in details. Finally, the degree of influence on the logistics expenses incurred by shippers using railway freight transport is derived.
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  • Chikara HIRAI, Taketoshi KUNIMATSU, Norio TOMII, Shigeki KONDOU, Motos ...
    2009 Volume 50 Issue 1 Pages 8-13
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    In the event of an accident on a railway line, the dispatcher responsible for train rescheduling on the line initially tries to stop related trains to ensure safety. In particular, if the accident causes blockage of the line for a long time, the dispatcher must decide which trains should keep running and which should be stopped. Moreover, the locations of the trains to be stopped also need to be decided appropriately at that point. This decision-making process is referred to as train stop deployment planning. In this paper, we propose an algorithm using a Petri-net-based modelling approach as a solution to this problem, and outline the numerical results produced.
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  • Yoshihiro WATANABE, Hiroshi HAYA, Masahiro SHINODA, Hirokazu OOMURA, T ...
    2009 Volume 50 Issue 1 Pages 14-19
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    The application of a health-monitoring system to railway structures is currently under discussion, and several prototype systems have already been implemented and tested. Those systems, often referred to as health-monitoring systems, are expected to have a positive effect on maintenance for structures. We have developed a health-monitoring system in which two methods of data collection can be selected: one uses RFID tags and a PDA (Personal Digital Assistant) and the other uses a wireless radio network (ZigBee, IEEE 802.15.4) and a cellular phone network. This paper gives an overview of our sensor data collection system and its application to railway structures.
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  • Yutaka SAKUMA, Atsushi IDO
    2009 Volume 50 Issue 1 Pages 20-25
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    Separated flow around the front end of a 1/5-scale vehicle model in a large-scale wind tunnel was examined through flow visualization using tufts and measurement of surface pressure distribution and aerodynamic drag. Various sizes and shapes of front-end edges for the vehicle were used in the experiments. The results indicated that shapes with edges rounded as elliptic arcs effectively reduce the separated flow, and that they can be used as a design guide for the front ends of vehicles on meter-gauge railway lines. The advantage of the experiments on separated flow in the large-scale wind tunnel was clearly shown by comparing the results with those previously obtained from a small-scale wind tunnel using a 1/20-scale model.
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  • Takeshi SUEKI, Mitsuru IKEDA, Takehisa TAKAISHI
    2009 Volume 50 Issue 1 Pages 26-31
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    Aerodynamic noise is a major source of wayside noise generated along high-speed railway lines, making it important to reduce the phenomenon. To this end, a new aerodynamic noise reduction method that involves covering the surface of objects with a particular porous material has been developed. To verify its aerodynamic noise reduction effects, wind tunnel tests using cylinders and a high-speed pantograph were conducted, and the noise produced was measured. The results showed that the noise generated from the cylinders and the high-speed pantograph were reduced by the application of porous materials, thus confirming that the method is effective in reducing such aerodynamic noise.
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  • Toshiki KITAGAWA
    2009 Volume 50 Issue 1 Pages 32-38
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    Railway noise from conventional meter-gauge lines in Japan mainly consists of rolling noise and traction-motor fan noise. Rolling noise is generated by vertical vibration of the wheel and rail, which is induced by relative displacement between the two due to the roughness on their surfaces. Through field tests, it was found that the excitation of rolling noise is determined by both the wheel/rail roughness and the vibratory behaviour of rolling stock and tracks. A theoretical model for rolling noise (such as TWINS) was then applied to Japanese railways, with the predictions showing a close correlation to the measured values. In terms of noise spectra, the rail was found to contribute more to rolling noise than the wheel in much of the frequency range. An attempt to estimate the effect of wheel and track parameters on rolling noise was also made using the TWINS model. The stiffness of the rail pad was found to affect the balance between the rail and sleeper components of noise, and additional damping for the rail was deemed effective in reducing the rail component of noise.
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  • Takafumi INOUE, Hiroaki SUZUKI, Keiko KIOKA, Hajime AKATSUKA, Masayosh ...
    2009 Volume 50 Issue 1 Pages 39-44
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    Psychological aptitude tests, which are highly suitable for securing the currently required levels of safety, contribute to the establishment of a safer railway environment. We carried out four new tests on 1,484 train operation staff (aged 18 - 63) and analyzed the correlation between the results of the current/new tests and staff members' history of causing railway accidents or transport disorder. A new set of tests was proposed based on the results of this analysis.
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  • Shingo MATSUMOTO, Toru SHIBATA
    2009 Volume 50 Issue 1 Pages 45-48
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    We performed quantitative evaluation of the possible effects of removing the obligation for cars to come to a complete stop before proceeding at level crossings in Japan. We carried out field investigations objective to vehicular traffic and evaluated safety under current conditions concerning traffic situations where vehicles cross train lines. We then evaluated safety by removing the temporary stop obligation in a traffic experiment over a level crossing using a driving simulator. Comparing the results of the two evaluations clearly demonstrated that accidents and train delays increase at level crossings with heavy traffic.
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  • Hiroharu ENDOH, Koji OMINO, Hiroaki SHIROTO, Mitsugu SAWA, Katsuji TAN ...
    2009 Volume 50 Issue 1 Pages 49-55
    Published: 2009
    Released on J-STAGE: March 04, 2009
    JOURNAL FREE ACCESS
    A wind tunnel experiment was conducted in order to study the effects of train-generated drafts on human postural stability. In the experiment, 29 people were exposed to a transient wind force similar to a draft from a passing train, and the results suggested that both wind speed and wind duration affect postural stability. In this paper, we estimated the tolerance of postural stability against transient wind based on a statistical model and a physical model, and discussed the validity of these models.
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