It is very important to understand the mechanism of track deterioration and predict track settlement or track irregularity growth rate for reducing track maintenance costs and designing new track structures. The authors established a track settlement prediction model which consists of a vehicle/track dynamic model and a track settlement law. The adequacy of the prediction model was roughly validated comparing with track site measurements carried out over five years. The track settlement law was established based on ballast settlement experiments in which applied loads were simple but practical loading conditions are not so simple. In this paper, the effect of the distance between leading and trailing axles of a bogie on the interaction between the responses, such as rail seat force and sleeper displacement, excited by the leading and trailing axles has been studied with the focus placed on vehicle speed, unsprung mass, the stiffness of track structures and rail type.

View full abstract

For track maintenance to be both effective and economical, it is essential to predict the dynamic behavior of rolling stock when subjected to track irregularities. For this purpose, we identified rolling stock lateral dynamic characteristics and created models to predict this dynamic behavior in vehicles on curved track sections. The actual noncompensated lateral acceleration was used as the input signal on the model in order to predict lateral acceleration at low frequencies, and alignment and cross-level for that in the middle frequency range. In the middle frequency range, the lateral axle force prediction model was the same as that used for lateral acceleration. With these models, it proved possible to understand the relationship between track geometry and rolling stock lateral behavior.

View full abstract

This paper describes the design and implementation of a common information infrastructure for passenger support systems. Based on this infrastructure, we have developed various guidance systems for use not only by the transportation disadvantaged, including visually-impaired and wheelchair users, but also by non-impaired people. By using the common infrastructure, we can build various guidance systems in a more cost-effective way. We have achieved this goal by developing a common access interface to user position databased on radio frequency identification (RFID) technologies and a method to describe guidance data which can be used for a variety of guidance systems. We have also developed prototype guidance systems based on this common information infrastructure.

View full abstract

CyberRail is an information technology (IT)-based infrastructure or system concept on which a new generation of railway services is founded. In other words, each railway operator will be able to develop its own new business model based on it to improve the quality of railway transport, which will let railway business regain a pivotal position in world mobility. To realize this objective, there are two basic factors: travel demand and the more difficult pinpointing of passenger locations at any given time. This paper explains a trial approach to realize a partial realization of CyberRail functions, particularly from the viewpoint of how to track passenger locations.

View full abstract

A hybrid method that combines the calculation of unsteady flow by large eddy simulation (LES) with the evaluation of acoustical performance by a compact Green's function has been proposed to provide detailed information on the flow vortices that contribute to aeroacoustic sound generation. This paper numerically verifies the noise reduction mechanism of pantograph horns with periodic holes and proves that the intermittent flow through holes suppresses the strength of dipole sound sources at the shear layer and collapses the large two-dimensional structure of sound sources in the spanwise direction.

View full abstract

Noise levels measured at points near Shinkansen tunnel portals include both the ordinary wayside noise and that radiating from tunnel portals, making them generally higher than elsewhere. To effectively reduce the noise levels at such locations, therefore, it is necessary to understand the contributions of both noise components. This paper describes a model used to predict the noise from a road traffic tunnel portal and applies it to Shinkansen noise. It has been confirmed that the model would be valid for predicting Shinkansen noise, if some modifications were made. Furthermore, higher sound barriers near a tunnel portal and the installation of sound-absorbing materials on tunnel inner walls are proposed as countermeasures and their effects are estimated on the basis of the modified prediction model.

View full abstract

In order to identify the vibrational characteristics influencing motion sickness experienced on trains, a poll of approximately 4,000 commercial passengers was carried out and vibration measurements taken on each train involved. When the results were summarized, it was revealed that the ratio of passengers who felt motion sickness on tilting trains was higher than that on non-tilting trains. Low frequency lateral motions in the range 0.25 to 0.32 Hz highly influenced the degree of motion sickness. Unlike seasickness, vertical motion effects were not apparent and there was a wide variation in susceptibility to motion sickness, with data from women and young people showing them to be more susceptible. Traditional frequency weighting curves for evaluating vibrational discomfort were ineffective for motion sickness evaluation. Consequently, a new frequency weighting curve needed to be proposed.

View full abstract

To prevent visually impaired persons from falling from railway platforms, we performed an experimental study to evaluate the effect of widening the tactile ground surface indicators (TGSIs) that warn them when they are nearing the platform edge. The focus of the evaluation was the detectability of dot tiles and the stopping distance required after they had been detected. As a result, it was not only proved that the typical width of 300 mm is effective, but also that adding 100 mm improves that effectiveness. The detection rate reached 100% when the width was 600 mm.

View full abstract

The dynamic response of railway bridges is a problem of the resonant response of girders that occurs because bridges are excited at a constant period by running trains. In general, this is referred to as "the speed effect of multiple-axle moving loads." In this study, vehicle running tests were performed to examine 56 bridges of various structural types and span lengths. The impact factor was measured to be about 1.0 on four girders, and the damping ratio as low as 0.02. Based on the results of these running tests and numerical analysis, a revision of the railway design standard was proposed, to cope with the speed-up of trains.

View full abstract

The effectiveness of the shear reinforcement of stirrups in deep beams has yet to be satisfactorily verified. Therefore, in the past, their effectiveness was not considered in the design of reinforced concrete (RC) structures when the shear strength of deep beams was calculated. In this research, model load tests of deep beams with stirrups were performed to examine their shear strength. As a result of the experiments, it was verified that the shear span and the shear reinforcement ratio influence the effectiveness of the shear reinforcement. A method of evaluating shear strength of deep beams with stirrups proposed.

View full abstract

The Design Standard for Concrete Railway Structures, which is itself a revised edition of the 1992 standard, has been established by fully adopting the structural performance verification design method. The new design standard outlined in this paper can be applied not only to JR structures, but also to those of other railway companies.

View full abstract