Bench tests for existing railcars are effective for measuring their dynamic performance. However, to date it has not possible to duplicate the actual running conditions of one car to a multiple car train consist. This paper explains the development of a hardware-in-the-loop simulation (HILS) system composed of an actual car, a distributed real-time simulator, a real-time network and car end simulators that simulate the dynamic behavior of the end surfaces of adjacent car bodies. This report introduces the HILS system and shows the results of shaking tests on the actual car used to reproduce the running conditions of a three-car train in the HILS system.

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When a wheel slip occurs on a certain axle or when re-adhesion control is executed, the tractive effort of the wheel-slip axle changes, which causes pitching of the bogie and the carbody. As a result, weight on the other normally adhering axles changes, which may induce wheel slip.
This paper explains the development of a control system designed to reduce wheel slip induced by axle-weight changes caused by other wheel slips. To verify the effectiveness of the control method, a water spray wheel-slip test was conducted using an EH200-type DC electric locomotive.

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Suppression of vertical bending vibration is essential to improve ride comfort on railway vehicles. For this purpose, a primary suspension damping force control system is being developed. This paper describes the composition of the system and reports on the results from vehicle running tests on some Shinkansen lines using actual Shinkansen vehicles fitted with the developed variable primary vertical dampers. The results of these tests demonstrate that this system is effective in reducing vertical vibration acceleration in the first bending mode of the car body and improves ride comfort. In addition, a progress report is also given on its ongoing development.

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In this report, further insight was obtained into earth pressure characteristics of the weathered layer behind slope protection work through laboratory tests based on results from investigations into the actual cutting slopes. Experiments were performed using models built on the measured conditions of weathered layers as determined by the above investigations. The outcome showed that it was possible to reproduce the earth pressure of the weathered layer as obtained from the experiments by considering the friction of the back surface of slope protection work. An evaluation method was then developed on the basis of results from the experiments.

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The safety of railway line sections against strong winds can be improved by setting up anemometers in locations where wind speeds frequently exceed the critical wind speed of overturning. In order to ensure optimum location of the anemometers, wind speed values need to be estimated over an N-year return period along railway lines. This paper introduces a method to estimate over a given return period the values of the maximum instantaneous wind-velocity along railway lines at interval of 100m, by using two kinds of numerical simulation techniques (the meteorological model and the Computational Fluid Dynamics model) and a topographical factor analysis.

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The design bearing capacity of piles can be calculated by multiplying the characteristic value with its corresponding resistance factor. In this study, we proposed a method for calculating these parameters from a loading test database of several different construction methods. Initially, we proposed the formula for calculating the characteristic value by using results from a ground investigation. Secondly, we proposed the resistance factor obtained from the statistical analysis of the loading test database by use of the first-order reliability method. The proposed method can be used to compare the effectiveness of various pile construction methods with the same reliability.

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Estimation of earthquake clusters expected to occur in a certain area together with their probability occurrence are required to evaluate the seismic risk to railway structures and vehicles. In this study, a calculation method is proposed for obtaining a set of earthquake time histories and their occurrence probabilities by combining a seismic hazard analysis and estimation of strong motion. Earthquake ground motion in the Tokyo region was then estimated using the proposed method in order to create an example of its applicability. It was then confirmed that seismic risk to railway structures and vehicles can be evaluated by using the proposed method.

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It is well known that the earthquake response of a pile-supported structure is strongly affected by dynamic soil-pile interaction. When the structure is subjected to severe ground motion, the soil behaves in a nonlinear manner. Two kinds of soil nonlinearity will affect the characteristics of dynamic soil-pile interaction. One is the nonlinearity which appears in the soil surrounding the pile and the other is the nonlinearity which appears in the free-field. The nonlinearity of soil surrounding the pile is caused by the inertia force transmitted from the superstructure onto the pile head (i.e., local-nonlinearity). Soil nonlinearity in the free-field is caused by the transmission of shear waves (i.e., site-nonlinearity). Various tools based on the Sway-Rocking model have been developed to analyze nonlinear dynamic soil-pile interaction. Most of these methods, however, only take into account local-nonlinearity effects. Therefore, a methodology to evaluate the effects of both local-nonlinearity and site-nonlinearity are developed in the paper. The accuracy of this method is confirmed by comparing simulated and experiment results.

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A Committee for Design Standards for Railway Structures & Commentaries [Foundation and Retaining Structures] (Chairman Prof. Osamu KUSAKABE, Tokyo Institute of Technology, Vice-chairman Prof. Junichi KOSEKI, Tokyo University) was established in 2005 to draft a revised version of "Design Standards for Railway Structures & Commentaries [Foundation and Retaining Structures]" presented at the last committee meeting in July 2008. The revised sections were "an introduction to performance based design"; "design model revision taking into account the subgrade reaction modulus" and "an introduction to new foundation materials and foundation construction methods". This paper discusses the recent trends in railway foundation design technology, and highlights from the contents of the revised version.

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