Abstract: Natural winds are turbulent flows and boundary layers exist near the surface of the actual ground, so that there is a possibility that the aerodynamic forces acting on train/vehicles from natural winds differ from uniform flows. Accordingly, full-scale models of a train/vehicle and a viaduct were constructed in a windy area, and wind characteristics and aerodynamic forces acting on the vehicle models were measured. Wind tunnel tests were conducted to simulate the turbulent boundary layer flow, and these test results agreed well with field tests.

Abstract: A method has been developed for predicting the aerodynamic noise from the bogie of a high-speed train using a two-dimensional microphone array in a low-noise wind tunnel. First, the flow velocity in the rail direction was measured in a field test at several points along the sleeper direction under the train car. Second, the flow distribution was reproduced precisely in a low-noise wind tunnel. Third, aerodynamic noise generated by the bogie (qaerodynamic bogie noiseq) was estimated from the noise source distribution measured with a two-dimensional microphone array. Finally, based on the experimental results, the noise generated from the lower part of the car (i.e. the aerodynamic noise estimated through the proposed method and the rolling and machinery noise estimated in a previous study) was compared with field test data measured near the track. The estimated lower part noise levels showed good agreement with those measured in the field test. This suggests that the proposed method is valid for the quantitative estimation of aerodynamic bogie noise. It was also shown that the contribution of the aerodynamic bogie noise is greater than the rolling and machinery noise, especially in the low-frequency region.

Abstract: In order to evaluate the axial force of a continuous welded rail quantitatively in a simple manner, a method was developed to measure axial force based on the natural frequency. However, the accuracy of this method is insufficient because of certain variations in track condition. This study extracted factors which influence measurement accuracy and proposed an error correction method using track finite-element analysis for the purpose of improving the accuracy of this measuring method. Furthermore, measurements were taken of the natural frequency and axial force of a rail on a real track in order to validate the proposed method.

Abstract: The analysis of the whole model of train-induced vibration, which consists of the moving train, the track, the supporting infrastructure, the ground, and the building, is currently too large to solve. The authors thus proposed a numerical simulation method by combining two separate dynamic analysis models. One is an analysis model of the dynamic interaction between the moving train and the track-structure system for calculating excitation force. The other is a three dimensional dynamic analysis model of the supporting structure, the ground, and the building for calculating the propagation of vibration.

Abstract: In Japan, four welding processes have been generally adopted for producing continuous welded rail (CWR): flash welding (FW), gas pressure welding (GPW), enclosed arc welding (EAW), and thermit welding (TW). Thermit welding method is the most popular rail welding process in Japan. The reliability of the thermit welds is high, because the failure rate has only been about 0.004 % over the last 10 years in Japan. However, recently there have been many cases where thermit welds are judged to be defective due to surface defects. Surface defects are often observed when welding new and worn rails. Welding test results show that surface defects are caused by gas generated from the contact of luting sand with molten steel which enters gaps between the welding mold and rail surface.

Abstract: The improvement rate of countermeasures adopted in constructing a second track on an embankment on soft ground is determined empirically due to unknown factors such as the deformation properties of soft ground. In this study, centrifuge model tests were performed to grasp the deformation properties of soft ground for such construction cases. Based on the test result, a new countermeasure was proposed, which has high horizontal support performance and combines deep mixing wall-type ground improvements and cement-mixed gravel. The proposed method having the same improvement rate as deep mixing was confirmed as being able to reduce the deformation of the embankment and the surrounding ground.

Abstract: It is necessary for train dispatchers to share risk-related information with their team members or superiors in order to deal with abnormal train traffic control situations. A training method was therefore developed to give train dispatchers communication skills. The training included risk scenarios, points to remember in terms of communication skills and a training program. A list of 45 key communication points to remember was also developed, which was designed to promote understanding about communication skills through regular use. This training method can easily be introduced into actual train traffic control fields. Trial experiments were conducted with actual train dispatchers which confirmed the effectiveness of the method.

Abstract: Financially supported by the New Energy and Industrial Technology Development Organization in Japan, the Railway Technical Research Institute has co-developed a flywheel energy storage system in association with KUBOTEK, FURUKAWA ELECTRIC, MIRAPRO and YAMANASHI prefecture. The flywheel system was chosen as an energy storage medium because in terms of life span, cost, capacity and output power, flywheel energy storage systems offer more advantages than other energy storage systems. It stores energy in the form of kinetic energy. Therefore, there is no electrochemical damage. This paper first describes the effect of the flywheel energy storage system, and then presents details of the equipment used in a demonstration test.

Abstract: As water is related to many deterioration mechanisms affecting concrete structures, knowledge of water movement behavior in concrete is very useful for the effective maintenance of these structures. In this study, based on many data obtained from monitoring sensors embedded in concrete samples, it was clarified that properties of water penetration into concrete surfaces differ according to component materials, mixing proportions and curing methods of the concrete. It was also made clear that water penetration behavior into the interface between the concrete and the section repair materials depends on pretreatment methods applied before addition of the restoration materials.

Abstract: For electric railways, it is preferable for the tension and height of overhead contact lines to be constant to maintain satisfactory current collection performance. Since overhead contact lines expand and contract according to temperature change, an automatic tension balancer is generally installed at the terminations. However, the tension of overhead contact lines is not always constant because of tension fluctuations in automatic tension balancers and the gradient of the yokes. In addition, contact wire wear causes its mass to decrease. This also affects the contact wire tension and height. The authors performed a theoretical study and a simulation. As the results of them, the authors clarified the effect of temperature change and contact-wire wear on current collection performance.

Abstract: Work has been conducted to develop REBCO (Rare-Earth Barium Copper Oxide) magnets for Maglev. REBCO is one of several high temperature superconducting materials and has a high current density at high temperatures and in high magnetic field environments. The REBCO coated conductor will make it possible to raise the operating temperature of on-board magnets without increasing the coil weight. Since liquid helium is unnecessary for cooling REBCO coils, magnet operation is easier than that with low temperature superconducting magnets. The aim of this research is the development of a real-size REBCO coil and demonstration of its actual magnetomotive force on Maglev. This paper describes the conceptual design of the on-board REBCO magnet and the experimental production of racetrack pancake coils which constitute the real-size REBCO coil.

Abstract: Preventing accidents and incidents depends on gaining a maximum amount of information about the situations in which these events occurred and about what actions were taken by the people involved in these events. Therefore, the authors developed a hearing investigation technique. And as a result of having tried this technique, they confirmed that they could collect more the data about the background factors than before. Moreover, they developed an educational program that consists of a five-step of exercise and explanation. And they confirmed that the participant's investigative attitude becomes proper.

Abstract: Ballasted track is widely as a main track structure and requires regular maintenance because track geometry deteriorates under the influence of dynamic loads. Therefore, several pieces of research into prediction and prevention of ballasted track deterioration, and maintenance of deteriorated ballasted track have been conducted by RTRI or other organizations around the world. This paper introduces some of the results obtained from the recent research into ballasted track carried out by RTRI and suggests possible future developments in this field.

Abstract: This study attempts to develop a method for identifying "bottleneck" stations on the inter-regional public transport network. Investing in these bottleneck stations enables the network to be more convenient. First, a method for identifying bottleneck stations on the network was formulated based on multi-objective optimization with a generic algorithm. Second, a system was developed to automatically identify bottleneck stations in a manner which makes them visible. A network outlining the actual inter-regional network in Japan was constructed. The results of numerical experiments on this network suggest that bottleneck stations may be located not only in the metropolitan areas but also in principal cities in the countryside.

Abstract: Wayside environmental problems in railways largely involve noise, ground vibration and tunnel micro-pressure wave. This review describes the results of recent studies into these issues conducted by Railway Technical Research Institute.

Abstract: This study aims to develop a model of passenger behavior when choosing trains from among various types of train service such as local and rapid services in urban railways, in order to evaluate passenger flows. This paper describes an online survey method for obtaining passenger activity data using departure information display images. A disaggregate demand model was developed for train choice behavior based on the survey data which were collected using the method. The developed model is put into practice by means of an application named "Train-Choice Model Viewer", which can calculate the time series data of passengers' volume at stations and in trains. It makes it possible to simulate the congestion level on each train and in each station when the time schedule is input.

Abstract: Elastic rubber materials such as rail pads are used on railway tracks in order to absorb vibrations and impact forces generated by passing trains. For example, rail pads reduce vibrations transmitted through the rails to structural track components such as rail fasteners and track slabs. The performance of rubber materials changes with temperature. Thus, there is a concern that the vibration reduction performance of elastic track materials may decrease at low temperatures because of the higher resulting stiffness. Field tests were conducted at the same point on a concrete viaduct in summer and winter to evaluate the influence of ambient temperature on the vibration and noise reduction performance of elastic track materials. The results showed that vibrations in some structural components under the rail pad increased at low temperature, which agrees with the track theory of the track vibration.

Abstract: A rapid prototyping bogie (RPB) has multiple actuators to emulate missing bogie components. In the original RPB hybrid control system, deterioration in the control performance, which was caused by dynamic coupling between the multiple actuators, was observed during the RPB performance tests. To solve this issue, a new controller was developed, based upon the dynamically substructured systems (DSS) method, and trialled on an existing proof-of-concept test rig. Through random excitation tests, it was confirmed that the actuators were well controlled. As a consequence, the DSS approach was determined as a viable framework for future research into the RPB system.

Abstract: Generally braking performance of train sets is evaluated by stopping distance or deceleration. However, stopping distance and deceleration are performance indices established for a whole train set, and do not represent performance of each car individually. For more detailed analysis of detail braking performance, it is useful to have the braking force in each car. This paper describes a method designed to estimate the braking force in each car based on the acceleration and coupler force, by using coupling devices as force sensors. Running tests results on an 18-car freight train using the devised method showed that it was possible to estimate the braking force of each car and that the estimated value was close to the theoretical value.