RTRI is engaged in R&D focusing on enhancing safety based on the Master Plan RESEARCH 2025. In the vehicle field, about 40 themes are implemented annually, targeting safety improvements and cost reduction. This paper introduces four recent achievements related to vehicle technology: running stability evaluation, a brake control method, a battery degradation evaluation method, and development of a train positioning system.

Maintenance of existing railway structures is becoming more and more important for safe and stable operation of railways. However, severe meteorological disasters in recent years have caused enormous damage to railway structures and hindered railway operations. The technical issues surrounding railway structures are wide-ranging, including labor-saving measures for maintenance of existing railway structures, disaster countermeasures, and early recovery measures after disaster. In this paper, we outline the direction of research and development, that the Railway Technical Research Institute is working on, related to maintenance of the existing railway structures, for example, inspection, diagnosis and reinforcement.

Railway systems are composed of many sub-systems such as overhead contact lines, vehicles, tracks and structures, which interact with each other and show complex dynamic behavior. In order to clarify the phenomena specific to railways caused by complex behaviors, the Railway Technical Research Institute has developed its own experimental technologies and measurement technologies. In this paper, first, as examples of our experimental technologies, we introduce three newly developed large-scale test facilities. Then, we introduce some of our measurement techniques for condition monitoring of tracks and structures are explained. Finally, we present the outlook for our future R&D policies to be implemented by effectively combining experiment/measurement technologies and numerical simulation techniques.

Train mechanical brakes convert kinetic energy into friction heat, which is emitted, to obtain braking force. Therefore, when stopping distance needs to be shortened to improve safety, the heat load on the brake increases. Friction material used for the brake is then required to have a thermally stable friction coefficient in addition to the heat capacity capable of accepting a given kinetic energy. This study therefore focuses on a method for evaluating brake friction materials used in Shinkansen, especially copper-based sintered alloy. We conducted experimental investigations, such as thermal analysis of solid lubricants and measurement of friction coefficient using a high-temperature friction test apparatus. This paper introduces the developed evaluation method of the heat resistance of base materials on the experiment results.

This paper presents an active steering system designed to ensure both the curving performance and running stability of a vehicle. Electro-hydraulic actuators installed in place of anti-yaw dampers generate a yaw moment between the carbody and bogie. The system detects curves with gyroscopes mounted on the vehicle. This configuration enables the reduction of wheel/rail lateral force without requiring complicated mechanical links in the bogies. The actuators also work as anti-yaw dampers during high-speed running to ensure running stability.

In recent years, railway companies have been introducing energy-saving technologies. This is leading to a growing need for methods able to accurately estimate the energy-saving effect of individual technologies. To this end, RTRI and JR West have been developing a method to estimate energy consumption during train operation using the Train Operation Power Simulator which reproduces commercial operating conditions. Because of the dispersion of energy consumption in commercial operations, it is important to be able to faithfully reproduce commercial operations. Therefore, we have developed a method to reproduce commercial operation utilizing commercial running data obtained from a Train Data Collection Device. Moreover, we have achieved a practical calculation time to estimate the energy-saving effect.

Geosynthetic-Reinforced Soil (GRS) integral bridge is a bridge that rigidly joins a girder and a reinforced soil abutment. This paper describes an outline of our new joint structure connecting a prestressed concrete T-shaped (PCT) girder and an abutment, which has been an important issue in developing GRS integral bridges using PCT girders. In addition to a design method for this joint structure of a PCT girder and an abutment, unique points of a design method for GRS integral bridge with use of PCT girders are introduced.

In mountain tunnels, floor heave may gradually progress. However, the mechanisms underlying this phenomenon are not yet fully understood. Therefore, no countermeasure design method has to date been established. In this study, we first conducted a literature review of floor heave cases to study the underlying mechanisms. Then, drawing on the insights gained through the literature review, we reproduced the estimated mechanisms in a model experiment. Based on the results of these experiments, this paper proposes an explanation of the floor heave mechanism and a suitable countermeasure against this phenomenon. The effect of the countermeasure was evaluated by numerical analysis.

Recent years have seen the collapse of embankments due in many cases to heavy rain in Japan. It is difficult to re-compact embankments which have suffered this type of collapse, because the collapsed soil contains a large amount of water. Another problem is that existing embankments in Japan are often constructed of materials which do not comply with current regulations of Japanese railway. For these reasons, conventionally, since the collapsed soil can’t be reused, purchased soil is used for restoration in Japan. However, this approach is both time consuming and costly. This paper proposes a new restoration method which reuses the soil from the collapsed embankment by utilizing the dehydrating effect of lime and by increasing soil strength by compaction.

The Railway Technical Research Institute (RTRI) has developed a new pantograph test facility, the “High-Speed Test Facility for Pantograph/OCL Systems,” to develop pantographs for high-speed trains, wear resistant contact strips, and so on. This test facility mainly consists of four parts: a rotational disk with attached contact wire which can rotate at high speed up to 500 km/h, exciters which reproduce lateral arrangement and vertical movement of overhead contact lines (OCL), an energizing device which applies large current to a pantograph up to 1000 A, and environmental control devices which can control temperature from -20 to +40°C and humidity from 10% to 90% in test chamber. This paper shows the function, performance, and usage example of this test facility.

Resonance in high-speed railway bridges is one of the sources of concern for ride comfort and catenary damage. In severe cases, countermeasures are required. However, detecting resonance requires a vast number of on-site measurements. This study develops a drive-by method for detecting resonant bridges as a train is running. The proposed method consists of signal processing for extracting vibration components specific to resonant bridges and a process of identifying differences between the lead and last vehicles. Results from a practical application of this method confirmed that it was possible to extract resonant bridges and the resonant states of the extracted bridges were confirmed by on-site measurement.

This paper proposes a new configuration for an instrumented wheelset, which is used to measure wheel/rail contact forces to assess running safety and evaluate curving performance of railway vehicles. Lateral force, which is a component of the wheel/rail contact forces, is measured as strains which are caused by the bending deformation of the wheel web in a conventional instrumented wheelset. According to this measurement principle, the measured lateral force is affected if a wheel load is applied, which reduces the accuracy of lateral force measurement. This paper describes in detail a novel instrumentation method for measuring the lateral force which can reduce the influence of the wheel load by using the shear strains inside the holes of the wheel web.