Tetsuya TAKATA’s research while affiliated with The Karachi Electric Supply Co. Ltd. and other places

Railway tracks must be managed appropriately because their conditions significantly affect railway safety. Safety is ensured through inspections by track maintenance staff and maintenance based on measurements using dedicated track geometry cars. However, maintaining regional railway tracks using conventional methods is becoming difficult because of their poor financial condition and lack of manpower. Therefore, a track condition diagnostic system is developed, wherein onboard sensing devices are installed on in-service vehicles, and the vibration acceleration of the car body is measured to monitor the condition of the track. In this study, we conduct long-term measurements using the system and evaluate changes in the track conditions over time using car-body vibration data. Filed test results showed that sections with degraded tracks were identified using car-body vibration data. The track degradation trend can be constructed using the results obtained. Furthermore, this study demonstrated that the track maintenance effect could be confirmed. A method for improving train position using the yaw angular velocity is proposed. The track irregularity position can be shown more clearly by monitoring the track condition using position-corrected data using the proposed method. It is also shown that the time-frequency analysis of measured car-body vertical acceleration is effective for evaluating the track condition more clearly.

Monitoring the condition of railway tracks effectively increases the safety of regional railways. A system that uses a compact on-board sensing device was previously developed for monitoring the track condition of regional railways. However, this system does not consider the running speed of the vehicle. In this study, we propose two new methods for diagnosing the condition of tracks considering the travelling speed of the vehicle: one based on the Mahalanobis distance and the other that uses Gaussian process regression. After conducting a test study to verify the effectiveness of the proposed methods, the results showed that both approaches can provide an accurate diagnosis when considering the influence of speed.

Monitoring the condition of railway tracks effectively increases the safety of railways. A system that uses a compact on-board sensing device was previously developed for monitoring the track condition of railways. The system's position identification method uses GPS map-matching.However, this system had an error of several tens of meters depending on GPS reception conditions. In this study, the position correction method was tested using curvature calculated from yaw angular acceleration. The results of the test study indicated that it is possible to diagnose the location of track irregularities more clearly.