Major Results of Research and Development in Fiscal 2023

This publication is a collection of the major results obtained from research undertaken by the Japanese public body, the Railway Technology Research Institute, in 2023. We would like to take this opportunity to thank all JR companies in particular and all the research centers, universities, industrial partners and other entities which have offered their cooperation, commitment and support to achieve these results and without whom none of this work would have been possible.

Ⅰ. Improvement of Safety

1. Method for detecting huge earthquakes using multiple ocean bottom seismometer data

  • We have developed a method for detecting huge earthquakes based on exceedances of thresholds by multiple ocean bottom seismometers, which is easy to integrate into earthquake early warning system for railways.
  • By using attenuation relations and site amplification characteristics estimated from ocean bottom seismometer data, it is possible to set thresholds with high reliability for each seismometer.

  • We have developed a method for detecting huge earthquakes based on exceedances of thresholds by multiple ocean bottom seismometers, which is easy to integrate into earthquake early warning system for railways.
  • By using attenuation relations and site amplification characteristics estimated from ocean bottom seismometer data, it is possible to set thresholds with high reliability for each seismometer.

2. A method for efficiently and precisely calculating site-specific design earthquake motions

  • We developed a method that can calculate site-specific design earthquake motions within about a day.
  • In addition to the existing parameter of earthquake motion amplitude, a new parameter of earthquake motion duration is taken into account to realize precise calculation of earthquake motion.
  • It enables the design of railway structures according to the characteristics of earthquake motions at each construction site.

  • We developed a method that can calculate site-specific design earthquake motions within about a day.
  • In addition to the existing parameter of earthquake motion amplitude, a new parameter of earthquake motion duration is taken into account to realize precise calculation of earthquake motion.
  • It enables the design of railway structures according to the characteristics of earthquake motions at each construction site.

3. Running safety evaluation method for vehicle overturning caused by localized strong winds

  • We have developed a running safety evaluation method for vehicle overturning caused by localized strong winds such as building winds.
  • Numerical analysis that takes into account the shape and layout of the building enables accurate calculation of wind speed distribution in the wake of the building.
  • It can be used to evaluate running safety in locations where localized strong winds are expected (e.g., around high-rise buildings, exits of tunnels, ends of windbreak fences, etc.) and to study effective countermeasures for crosswind.

  • We have developed a running safety evaluation method for vehicle overturning caused by localized strong winds such as building winds.
  • Numerical analysis that takes into account the shape and layout of the building enables accurate calculation of wind speed distribution in the wake of the building.
  • It can be used to evaluate running safety in locations where localized strong winds are expected (e.g., around high-rise buildings, exits of tunnels, ends of windbreak fences, etc.) and to study effective countermeasures for crosswind.

4. Manual for investigating the deterioration degree of the ground behind slope protection work

  • We have developed a simple and low-cost test method to investigate the deterioration degree of the slope ground, which is important for the maintenance and management of the slope protection work, and have also prepared a manual for investigating the deterioration degree of the ground.
  • The deterioration degree is evaluated by measuring the penetration resistance of the rod if the slope ground is mainly soil, or the drilling resistance of the electric drill if the slope ground is bedrock.

  • We have developed a simple and low-cost test method to investigate the deterioration degree of the slope ground, which is important for the maintenance and management of the slope protection work, and have also prepared a manual for investigating the deterioration degree of the ground.
  • The deterioration degree is evaluated by measuring the penetration resistance of the rod if the slope ground is mainly soil, or the drilling resistance of the electric drill if the slope ground is bedrock.

5. Track irregularity estimation system based on looseness detection during for constructing a crossing structure under railway tracks

  • We have developed a compact track irregularity estimation system that can make early detection of loosening of ground (which is a sign of track settlement), and estimate the amount of track settlement for constructing a crossing structure under railway tracks.
  • Early detection of signs of track settlement and revision of the digging length will improve safety and reduce the cost of track maintenance.

  • We have developed a compact track irregularity estimation system that can make early detection of loosening of ground (which is a sign of track settlement), and estimate the amount of track settlement for constructing a crossing structure under railway tracks.
  • Early detection of signs of track settlement and revision of the digging length will improve safety and reduce the cost of track maintenance.

6. Measurement method of contact force and contact position between wheel and rail using shear strain

  • We developed a method for measuring lateral force using an instrumented wheelset that utilizes shear strain, as well as a method for measuring the contact position between the wheel and rail based on this approach.
  • Errors in derailment coefficients are reduced by up to 18%, enabling more accurate evaluation of running safety.
  • The contact position can be measured with an error of about 5 mm.

  • We developed a method for measuring lateral force using an instrumented wheelset that utilizes shear strain, as well as a method for measuring the contact position between the wheel and rail based on this approach.
  • Errors in derailment coefficients are reduced by up to 18%, enabling more accurate evaluation of running safety.
  • The contact position can be measured with an error of about 5 mm.

7. Automatic flaw extraction method for nondestructive inspection of bogie parts

  • We developed a method to automatically extract flaws by applying machine learning to magnetic particle testing images and ultrasonic testing waveforms. The accuracy of flaw detection is approximately 70% for the surface flaw image of the welding and more than 95% for the internal flaw waveform of the welding.
  • The constructed machine learning methods and models will facilitate the de-skilling of flaw detection tasks.

  • We developed a method to automatically extract flaws by applying machine learning to magnetic particle testing images and ultrasonic testing waveforms. The accuracy of flaw detection is approximately 70% for the surface flaw image of the welding and more than 95% for the internal flaw waveform of the welding.
  • The constructed machine learning methods and models will facilitate the de-skilling of flaw detection tasks.

8. Light section method contact wire wear measurement system for 360 km/h operation

  • We have developed a contact wire wear measurement system that enables measurement from a vehicle running at 360 km/h by means of coordinated control of cameras and laser light sources, and faster calculation of the residual diameter.
  • Measurement tests on Shinkansen vehicles have shown that the measurement error of the residual diameter of the contact wire is within 0.3 mm. This measurement system aims to improve the reliability of contact wire wear management and reduce the risk of wire breakage.

  • We have developed a contact wire wear measurement system that enables measurement from a vehicle running at 360 km/h by means of coordinated control of cameras and laser light sources, and faster calculation of the residual diameter.
  • Measurement tests on Shinkansen vehicles have shown that the measurement error of the residual diameter of the contact wire is within 0.3 mm. This measurement system aims to improve the reliability of contact wire wear management and reduce the risk of wire breakage.

9. Door pinch detection system that combines a door end rubber with a built-in pressure-sensitive sensor

  • We have developed a door pinch detection system that combines a door end rubber with a built-in pressure-sensitive sensor and a non-contact power supply device to enable simple transmission of detection information to the driver’s seat.
  • The door end rubber with a built-in pressure-sensitive sensor can detect dragging due to pinching of intermediate objects or strings, which have been difficult to detect with conventional systems.

  • We have developed a door pinch detection system that combines a door end rubber with a built-in pressure-sensitive sensor and a non-contact power supply device to enable simple transmission of detection information to the driver’s seat.
  • The door end rubber with a built-in pressure-sensitive sensor can detect dragging due to pinching of intermediate objects or strings, which have been difficult to detect with conventional systems.

10. Evaluation method for conductors’ safety check skills using VR technology

  • We developed a method to quantify conductors’ eye movement during platform safety checks using VR technology and to evaluate the differences in eye movements between instructing conductors and trainees.
  • Using the results of this study, it is possible to evaluate whether the eye movement of conductors is closer to that of an instructing conductor or a trainee. This allows us to compare the effectiveness of training programs and will contribute to a more effective teaching.

  • We developed a method to quantify conductors’ eye movement during platform safety checks using VR technology and to evaluate the differences in eye movements between instructing conductors and trainees.
  • Using the results of this study, it is possible to evaluate whether the eye movement of conductors is closer to that of an instructing conductor or a trainee. This allows us to compare the effectiveness of training programs and will contribute to a more effective teaching.

Ⅱ. Cost Reduction

11. Emergency diagnosis method for scour damaged bridges

  • We have proposed methods for estimating the exposure rate and the bearing capacity of the base of the foundation using an impact and vibration test to evaluate the stability of piers damaged by scour in a short period of time.
  • Based on the estimated bearing capacity, the need for loading tests and reinforcement can be determined immediately, potentially reducing the restoration time by up to half.

  • We have proposed methods for estimating the exposure rate and the bearing capacity of the base of the foundation using an impact and vibration test to evaluate the stability of piers damaged by scour in a short period of time.
  • Based on the estimated bearing capacity, the need for loading tests and reinforcement can be determined immediately, potentially reducing the restoration time by up to half.

12. Low-cost girder movement restriction device provides improved restorability for existing steel railway bridges

  • We have developed a girder movement restriction device that uses bolted joints to control girder movement during large-scale earthquakes. This prevents sliding down from bearing caused by the movement and improves restorability.
  • This device can serve as an anti-bridge-collapse device during large-scale earthquakes at the same cost as conventional girder movement restriction devices.

  • We have developed a girder movement restriction device that uses bolted joints to control girder movement during large-scale earthquakes. This prevents sliding down from bearing caused by the movement and improves restorability.
  • This device can serve as an anti-bridge-collapse device during large-scale earthquakes at the same cost as conventional girder movement restriction devices.

13. Rebars arrangement method for joints of RC viaducts with considering the labor saving in construction

  • The nonlinear FEM was developed for examining the structural details of column-beam joints in RC viaducts, and clarified that the required proof strength was obtained even the spacing between re-bars in joints being doubled.
  • The proposed analysis can reduce the amount of rebar, which are difficult to construct the joints of viaduct, and achieve labor savings in rebar assembly and concrete casting.

  • The nonlinear FEM was developed for examining the structural details of column-beam joints in RC viaducts, and clarified that the required proof strength was obtained even the spacing between re-bars in joints being doubled.
  • The proposed analysis can reduce the amount of rebar, which are difficult to construct the joints of viaduct, and achieve labor savings in rebar assembly and concrete casting.

14. Back-side construction method for reinforced soil retaining walls applicable to narrow areas

  • We have proposed a method of constructing reinforced soil retaining walls that can be applied to narrow areas and does not require scaffolding.
  • Lightweight buried formwork and settlement-allowing members are combined and installed from the back side of the wall (embankment side).
  • This method allows for daytime construction even in areas close to commercial lines, eliminating the need for nighttime work that requires railway track closing. As a result, the construction period can be reduced by 30% and the construction costs by 15%.

  • We have proposed a method of constructing reinforced soil retaining walls that can be applied to narrow areas and does not require scaffolding.
  • Lightweight buried formwork and settlement-allowing members are combined and installed from the back side of the wall (embankment side).
  • This method allows for daytime construction even in areas close to commercial lines, eliminating the need for nighttime work that requires railway track closing. As a result, the construction period can be reduced by 30% and the construction costs by 15%.

15. Cylindrical roller bearings with ribs for conventional line electric railcar gear unit and its performance evaluation

  • We have developed a pinion support structure for conventional line electric railcars that uses cylindrical roller bearings with ribs. This design allows for an increase in the upper limit of the end play value, which is the total axial clearance of the bearings.
  • This approach reduces the need for end play adjustments that involve disassembling the gear unit, thereby allowing for labor saving during maintenance.
  • We confirmed that the bearing temperature and vibration of the proposed structure are equal to or lower than those of the conventional structure.

  • We have developed a pinion support structure for conventional line electric railcars that uses cylindrical roller bearings with ribs. This design allows for an increase in the upper limit of the end play value, which is the total axial clearance of the bearings.
  • This approach reduces the need for end play adjustments that involve disassembling the gear unit, thereby allowing for labor saving during maintenance.
  • We confirmed that the bearing temperature and vibration of the proposed structure are equal to or lower than those of the conventional structure.

16. Core image analysis technology for utilizing train-front images

  • We have developed and modularized functions for calculating positions on the railway track from train-front images, generating long-length railway track surface images, recognizing railway track side equipment, and assessing degradation levels.
  • By combining the developed modules, it becomes possible to efficiently develop applications that utilize train-front images.

  • We have developed and modularized functions for calculating positions on the railway track from train-front images, generating long-length railway track surface images, recognizing railway track side equipment, and assessing degradation levels.
  • By combining the developed modules, it becomes possible to efficiently develop applications that utilize train-front images.

17. Inspection support system using images of tunnel walls

  • We have developed an application that uses AI to extract deteriorations from images of tunnel walls and identify the overall health of the tunnel and areas requiring special attention.
  • We have developed a mobile projection mapping device that can continuously project the identified areas requiring special attention onto tunnel walls of various shapes.
  • This allows for reductions in both the time required for general tunnel inspection and the need for personnel.

  • We have developed an application that uses AI to extract deteriorations from images of tunnel walls and identify the overall health of the tunnel and areas requiring special attention.
  • We have developed a mobile projection mapping device that can continuously project the identified areas requiring special attention onto tunnel walls of various shapes.
  • This allows for reductions in both the time required for general tunnel inspection and the need for personnel.

18. Simple onboard track patrol support method using smartphones

  • We developed an onboard track patrol support application with high operability using smartphones.
  • By synchronizing the front-view video captured by the onboard track patrol support application with the measured data such as train speed and vibration acceleration, and displaying this information as subtitles on the video, it is possible to check the track condition at a desk.
  • This eliminates individual differences among workers and enables the reduction of skill requirements of onboard track patrol.

  • We developed an onboard track patrol support application with high operability using smartphones.
  • By synchronizing the front-view video captured by the onboard track patrol support application with the measured data such as train speed and vibration acceleration, and displaying this information as subtitles on the video, it is possible to check the track condition at a desk.
  • This eliminates individual differences among workers and enables the reduction of skill requirements of onboard track patrol.

19. Non-screw plate-shaped spring clip rail fastening method

  • We have developed a non-screw plate-shaped spring clip rail fastening method that eliminates the need for bolt retightening, along with a specialized tool for fastening and loosening.
  • The existing springs clips and bolts of the rail fastening system can be replaced with the newly developed specialized plate-shaped spring clips, fixing bolts, and fastening washers, allowing the rails to be secured without the need to replace the existing sleepers.

  • We have developed a non-screw plate-shaped spring clip rail fastening method that eliminates the need for bolt retightening, along with a specialized tool for fastening and loosening.
  • The existing springs clips and bolts of the rail fastening system can be replaced with the newly developed specialized plate-shaped spring clips, fixing bolts, and fastening washers, allowing the rails to be secured without the need to replace the existing sleepers.

20. Rail gas pressure welding method of low upset length without the process of bulge removal by hot shearing

  • We have developed a rail gas pressure welding method that reduces the upset length by 75% and minimizes the bulge at the weldment, allowing the omission of the bulge removal by hot shearing process.
  • By using this method, the weight of the existing welding apparatus can be reduced by 40%, increasing work efficiency, and reducing execution costs by 30%.

  • We have developed a rail gas pressure welding method that reduces the upset length by 75% and minimizes the bulge at the weldment, allowing the omission of the bulge removal by hot shearing process.
  • By using this method, the weight of the existing welding apparatus can be reduced by 40%, increasing work efficiency, and reducing execution costs by 30%.

21. System for prestressed concrete (PC) sleeper evaluation of health, focusing on vertical cracks

  • We developed a system that automatically extracts longitudinal cracks and evaluates their health using deep learning, in addition to clarifying the relationship between the length of longitudinal cracks and the load-bearing capacity of PC sleepers.
  • This system makes it possible to monitor the occurrence of longitudinal cracks and evaluate the health of PC sleepers along the entire route, thereby improving safety and streamlining maintenance and management operations.

  • We developed a system that automatically extracts longitudinal cracks and evaluates their health using deep learning, in addition to clarifying the relationship between the length of longitudinal cracks and the load-bearing capacity of PC sleepers.
  • This system makes it possible to monitor the occurrence of longitudinal cracks and evaluate the health of PC sleepers along the entire route, thereby improving safety and streamlining maintenance and management operations.

22. An automatic generation method of maintenance worker schedules at stations and depots

  • We have developed an automatic generation method of maintenance worker schedules at stations and depots.
  • Maintenance worker schedules can be generated within three minutes, taking into account work constraints and their priorities.

  • We have developed an automatic generation method of maintenance worker schedules at stations and depots.
  • Maintenance worker schedules can be generated within three minutes, taking into account work constraints and their priorities.

Ⅲ. Harmonization with the Environment

23. Verification of commercial line operation using a superconducting feeding system

  • We conducted the first operational verification of superconducting power transmission on commercial lines, both in Japan and abroad, with the approval of the Ministry of Land, Infrastructure, Transport and Tourism, aiming for the practical application and widespread adoption of the superconducting feeding system.
  • We have developed a compact and highly efficient refrigerator that can be installed along railway lines.

  • We conducted the first operational verification of superconducting power transmission on commercial lines, both in Japan and abroad, with the approval of the Ministry of Land, Infrastructure, Transport and Tourism, aiming for the practical application and widespread adoption of the superconducting feeding system.
  • We have developed a compact and highly efficient refrigerator that can be installed along railway lines.

24. Automatic method for creating energy-efficient train timetables by reducing powering energy and effective use of regenerative power

  • We have developed a method to automatically create energy-efficient train timetables by combining reductions in powering energy and effective use of regenerative power, and confirmed energy saving effects of 4.4 to 7.5% in case studies.
  • Reasonable train timetables can be created without altering the total travel time from the starting station to the terminal, while still accommodating speed limits and headways due to signalling facilities and other conditions.

  • We have developed a method to automatically create energy-efficient train timetables by combining reductions in powering energy and effective use of regenerative power, and confirmed energy saving effects of 4.4 to 7.5% in case studies.
  • Reasonable train timetables can be created without altering the total travel time from the starting station to the terminal, while still accommodating speed limits and headways due to signalling facilities and other conditions.

Ⅳ. Improvement of Convenience

25. Next-generation tilt control system compatible with high-speed driving

  • We have developed a tilt control algorithm that considers the velocity and acceleration of the carbody tilting, achieving quick and stable tilt control even at high speeds.
  • We have confirmed that this algorithm not only significantly reduces the motion sickness evaluation index but also suppresses the yawing motion characteristic of tilting vehicles.
  • It improves the ride quality of tilting vehicles in a wide range of train speeds.

  • We have developed a tilt control algorithm that considers the velocity and acceleration of the carbody tilting, achieving quick and stable tilt control even at high speeds.
  • We have confirmed that this algorithm not only significantly reduces the motion sickness evaluation index but also suppresses the yawing motion characteristic of tilting vehicles.
  • It improves the ride quality of tilting vehicles in a wide range of train speeds.

26. A method for constructing a three-dimensional vibration analysis model of a carbody for high-frequency ranges

  • We have developed a method for constructing a three-dimensional vibration analysis model that accurately reproduces carbody vibrations at high frequencies of 20 Hz and above, addressing issues with accuracy found in existing analysis model.
  • Natural frequencies up to 40 Hz can be estimated with an error of less than 5%, and deformed shapes can be reproduced.
  • It can be used to improve vibration characteristics by changing the carbody structure during vehicle design.

  • We have developed a method for constructing a three-dimensional vibration analysis model that accurately reproduces carbody vibrations at high frequencies of 20 Hz and above, addressing issues with accuracy found in existing analysis model.
  • Natural frequencies up to 40 Hz can be estimated with an error of less than 5%, and deformed shapes can be reproduced.
  • It can be used to improve vibration characteristics by changing the carbody structure during vehicle design.

Ⅴ. Basic Research

27. Simulation of seismic behavior of a train set

  • We have developed an analysis method that can calculate the seismic behavior of train sets, considering the effects of couplers, dampers between vehicles, and other coupling structures between vehicles.
  • The method can calculate a series of vehicle behaviors from pre-derailment to post-derailment and can be used as a tool to understand the specifics of derailment phenomena during earthquakes and to develop measures to prevent derailments and deviations.

  • We have developed an analysis method that can calculate the seismic behavior of train sets, considering the effects of couplers, dampers between vehicles, and other coupling structures between vehicles.
  • The method can calculate a series of vehicle behaviors from pre-derailment to post-derailment and can be used as a tool to understand the specifics of derailment phenomena during earthquakes and to develop measures to prevent derailments and deviations.

28. Estimation method for factors contributing to decision errors by train forward surveillance AI

  • We have developed a method to estimate the factors behind decision errors in AI used for train forward surveillance, with the goal of considering appropriate countermeasures.
  • Factor estimation was successfully completed for all 2,668 missed images from approximately 215 hours of train forward surveillance video.
  • The method can also be used to check performance when developing AI-based systems.

  • We have developed a method to estimate the factors behind decision errors in AI used for train forward surveillance, with the goal of considering appropriate countermeasures.
  • Factor estimation was successfully completed for all 2,668 missed images from approximately 215 hours of train forward surveillance video.
  • The method can also be used to check performance when developing AI-based systems.

29. Estimation method for wear mode of current collection materials with the consideration of sliding history

  • We have proposed a method for estimating the wear mode of current collection materials by considering not only the temperature rise of the contact points due to friction and current flow but also the heat accumulated in the contact strip and the condition of the wear surface.
  • This method can be used to clarify wear phenomena by considering the history of pantograph sliding conditions and contact wire installation configurations, and to explore measures for reducing wear.

  • We have proposed a method for estimating the wear mode of current collection materials by considering not only the temperature rise of the contact points due to friction and current flow but also the heat accumulated in the contact strip and the condition of the wear surface.
  • This method can be used to clarify wear phenomena by considering the history of pantograph sliding conditions and contact wire installation configurations, and to explore measures for reducing wear.

30. Accuracy enhancement of Earthquake Early Warning for railways using optical sensing technology

  • We proposed an earthquake monitoring network using optical sensing technology applied to existing optical fiber cables along railway lines and confirmed that seismic activity can be detected every five meters.
  • We proposed a method for rapid hypocenter determination, using data from multiple observation points with optical sensing technology, which offers high accuracy and immediacy for Earthquake Early Warnings.

  • We proposed an earthquake monitoring network using optical sensing technology applied to existing optical fiber cables along railway lines and confirmed that seismic activity can be detected every five meters.
  • We proposed a method for rapid hypocenter determination, using data from multiple observation points with optical sensing technology, which offers high accuracy and immediacy for Earthquake Early Warnings.

·A part of I.1 is collaborative research with East Japan Railway Company, Japan Agency for Marine-Earth Science and Technology and National Research Institute for Earth Science and Disaster Resilience. ·A part of I.6 is collaborative research with University of Iowa. ·A part of Ⅱ.11 was accomplished by Railway Technology Development and Promotion System of Ministry of Land, Infrastructure, Transport and Tourism. ·Ⅱ.12 is collaborative research with Kobe University and Nippon Chuzo K.K.. ·A part of Ⅱ.13 was accomplished by Railway Technology Development Subsidy of Ministry of Land, Infrastructure, Transport and Tourism. ·Ⅱ.14 is collaborative research with OKASANLIVIC.CO.,LTD. and K.K Enbine. ·Ⅱ.15 is collaborative research with TOYO DENKI SEIZO K.K. and NTN Corporation. ·A part of Ⅱ.17 was accomplished by Transportation Technology Development Promotion System of Ministry of Land, Infrastructure, Transport and Tourism. ·Ⅱ.18 is collaborative research with The University of Tokyo. ·Ⅱ.20 is collaborative research with Niigata University. ·Ⅱ.22 is collaborative research with Meiji University. ·A part of Ⅲ.23 was accomplished by Railway Technology Development Subsidy of Ministry of Land, Infrastructure, Transport and Tourism. ·Ⅴ.30 is collaborative research with Japan Agency for Marine-Earth Science and Technology and National Research Institute for Earth Science and Disaster Resilience.

Major Results of Research and Development