Train driving is characterized by late-night and early-morning shifts when operators may be prone to drowsiness. This study developed and evaluated a system aimed at maintaining and improving arousal level by presenting auditory warnings. First, auditory warnings were designed based on a survey of train operators' opinions. In our experiments, designated auditory warnings were scored and selected in terms of three requirements ("audibility," "distinctiveness," and "arousal function") under train noise. The result shows that the arousal effects of the warning auditory were confirmed by presenting the designed sound during a monotonous task with the train driver environment.

In order to enhance the safety of passengers seated in long seats, it is important to identify the risk to passengers in the event of a collision. In a prior study, case studies using numerical analysis showed that the installation of handrails reduced the secondary impact velocity of passengers' heads. The purpose of this study is to investigate the effect of handrails in reducing the severity of injury to passengers through a series of physical tests. The experiment results showed that the occupant behavior and the severity of injury to the occupants were dependent on the initial seating position, and that the severity of head and thorax injuries decreased significantly in the presence of handrails.

Deterioration caused by chloride ions may occur in some shield tunnels located in waterfront areas or near tidal rivers. In this paper, we propose a three-dimensional finite element analysis method for the maintenance of shield tunnels affected by chloride ions. In proposing this method, we developed a modeling method for deteriorated segment joints by reducing stiffness. In addition, we verified the validity of the method by loading tests of segmental lining specimens.

Impact loads from train wheels passing rail joints tend to cause fatigue cracks in steel bridges near the rail joints. In order to evaluate the effects of impact load on the fatigue of the deck system of a steel box girder, we carried out stress measurements on steel girders on an existing bridge. The results showed that the impact loads at rail joints generate two types of high frequency natural mode vibrations of around 40 Hz, and around 350 Hz. It was also shown that these vibrations lead to an increase in the range and cycle of stress at the welded joints of the deck system.

The authors developed a prediction equation for the shrinkage strain of concrete to cope with various design conditions of concrete structures. The developed equation allows input of the effects of cement types, aggregate shrinkage strain, and the application of liquid water, in addition to the conventionally indicated mix proportion of concrete and ambient relative humidity. The equation is formulated using a 3D material-structure interaction analysis system (DuCOM-COM3). The equation can explain the phenomena that is considered to be caused in part by concrete shrinkage, such as strain of concrete in prestressed concrete girders in service using blast furnace cement concrete.

This study aims to establish a test method for loading test tracks composed of a single set of rail fastenings for rail joints. The authors of this paper constructed FEM models for railway tracks which represent rail joint parts accurately and performed an FEM analysis. The FEM results are in good agreement with the results of a load test on a test track composed of multiple sets of rail fastenings. On the basis of the FEM model, the authors proposed a test method for loading test tracks composed of a single set of rail fastenings and compared the test results of a single set of rail fastenings with those of multiple sets of rail fastenings. The results show that rail head displacements and rail tilting angles obtained by a single set of rail fastenings are in good agreement with those obtained by multiple sets of rail fastenings. Therefore, it is concluded that the proposed method based on the FEM model is able to evaluate the performance of rail fastening systems for rail joints.

When a train repeatedly runs on a track, track irregularities, which are distortions of the track, gradually increase with repetition of wheel load. Tracks are normally inspected periodically so that maintenance can be carried out when a large track irregularities are detected. However, in rare cases, the magnitude of a track irregularity may rapidly increase locally. To ensure the safety of train operations, preventive maintenance is required to detect the signs of such rapid increases in the magnitude of irregularities and to perform maintenance before large irregularities occur. In this study, to identify in advance locations where large track irregularities are likely to occur, we developed a mathematical model that applies cluster analysis to historical data for track irregularities and maintenance records.

Rail corrugation causes noise, vibrations, and deterioration of track components, which increase the frequency of track maintenance work. However, a measurement method that efficiently evaluates the growth of rail corrugation has not been established. The authors of this paper have developed a monitoring system for rail corrugation that enables long-term remote measurement of rail vibrations by means of battery-powered accelerometers and a wireless sensor network. In this study, the relationship between vertical rail vibration characteristics and actual rail corrugation measured on commercial lines was investigated to verify the applicability of the developed system for identifying the growth process of rail corrugation.

A method for applying public communication lines to communication-based train control systems is proposed. Applying public communication lines to train control systems differs from when applying them to conventional systems in that transmission lines which cannot be controlled by railway operators, intervene between safety devices. Therefore, this paper presents a configuration where train control function and information transmission are independent of each other in order to build a system which meets safety critical requirements without depending on transmission lines. This paper also presents threats posed by information transmission functions from the perspective of the train control function and countermeasure requirements, as well as implementation methods which meet these requirements using current techniques.

Instrumented wheelsets are widely utilized in the railway industry to measure wheel-rail interaction force. In a conventional instrumented wheelset, the measurement accuracy of the lateral force is reduced due to the bending moment induced by the wheel load. The author has proposed a new configuration for an instrumented wheelset to reduce the influence of the wheel load on the measurement of the lateral force. This proposed configuration utilizes the shear strains of a wheel web as a measure of the lateral force. This paper describes the accuracy verification of the proposed configuration under a wheel rotating condition. Tests using a single-wheelset roller-rig were carried out and the test results show that the proposed method can reduce the influence of the wheel load even under a rotating condition.