Rail defects can pose significant safety risks in railway operations, raising the need for effective detection methods. Acoustic Emission (AE) technology has shown promise for identifying and monitoring these defects,...Rail defects can pose significant safety risks in railway operations, raising the need for effective detection methods. Acoustic Emission (AE) technology has shown promise for identifying and monitoring these defects, and this study evaluates an advanced on-vehicle AE detection approach using bone-conduct sensors—a solution to improve upon previous AE methods of using on-rail sensor installations, which required extensive, costly on-rail sensor networks with limited effectiveness. In response to these challenges, the study specifically explored bone-conduct sensors mounted directly on the vehicle rather than rails by evaluating AE signals generated by the interaction between rails and the train’s wheels while in motion. In this research, a prototype detection system was developed and tested through initial trials at the Nevada Railroad Museum using a track with pre-damaged welding defects. Further testing was conducted at the Transportation Technology Center Inc. (rebranded as MxV Rail) in Colorado, where the system’s performance was evaluated across various defect types and train speeds. The results indicated that bone-conduct sensors were insufficient for detecting AE signals when mounted on moving vehicles. These findings highlight the limitations of contact-based methods in real-world applications and indicate the need for exploring improved, non-contact approaches.展开更多
The railway network is increasingly becoming central to socio-economic development and the decarbonisation of transport,supporting its growth in compliance with the emission reduction targets set by the 2050 European ...The railway network is increasingly becoming central to socio-economic development and the decarbonisation of transport,supporting its growth in compliance with the emission reduction targets set by the 2050 European Green Deal.Thus,several programmes for the major network renewals and the construction of safe,resilient,and efficient high-speed(HS)lines have been implemented.In this scenario,some construction solutions have been introduced to enhance the durability and functionality of the railway infrastruc-ture,particularly for the ballasted track one.Among these design techniques,the asphalt or bituminous sub-ballast has emerged as a proven technology capable of improving the rail-way performance and durability.Derived from the road construction approach,asphalt sub-ballast has been used in the European HS and high-capacity(HC)lines since the 1970s,providing both structural and functional benefits.This article offers a critical review of the current knowledge on the asphalt sub-ballast applications,highlighting its technical characteristics and long-term performances.Functional,structural,and economic advan-tages have been assessed and analyzed based on laboratory scale and on-field experiences.Experimental data indeed confirm the effectiveness of asphalt sub-ballast in improving the track stability and load distribution,in providing better water drainage and in reducing fatigue induced phenomena.These enhanced properties lead to lower maintenance costs and operations,particularly those related to ballast tamping,as well as to an extended ser-vice life of the whole infrastructure.From the circular economy perspective,the re-use or recycle of wastes and by-products in these mixes amplifies the cost-benefit ratio,also improving their sustainability.展开更多
文摘Rail defects can pose significant safety risks in railway operations, raising the need for effective detection methods. Acoustic Emission (AE) technology has shown promise for identifying and monitoring these defects, and this study evaluates an advanced on-vehicle AE detection approach using bone-conduct sensors—a solution to improve upon previous AE methods of using on-rail sensor installations, which required extensive, costly on-rail sensor networks with limited effectiveness. In response to these challenges, the study specifically explored bone-conduct sensors mounted directly on the vehicle rather than rails by evaluating AE signals generated by the interaction between rails and the train’s wheels while in motion. In this research, a prototype detection system was developed and tested through initial trials at the Nevada Railroad Museum using a track with pre-damaged welding defects. Further testing was conducted at the Transportation Technology Center Inc. (rebranded as MxV Rail) in Colorado, where the system’s performance was evaluated across various defect types and train speeds. The results indicated that bone-conduct sensors were insufficient for detecting AE signals when mounted on moving vehicles. These findings highlight the limitations of contact-based methods in real-world applications and indicate the need for exploring improved, non-contact approaches.
基金Project funded under the National Recovery and Resilience Plan(NRRP),Mission 4 Component 2 Investment 1.4−Call for tender No.3138 of 16/12/2021 of Italian Ministry of University and Research funded by the European Union–NextGener-ationEU.Award Number:Project code CN00000023,Concession Decree No.1033 of 17/06/2022 adopted by the Italian Ministry of University and Research,CUP D93C22000400001,“Sustainable Mobility Center”(CNMS).Spoke 4–Rail Transportation.
文摘The railway network is increasingly becoming central to socio-economic development and the decarbonisation of transport,supporting its growth in compliance with the emission reduction targets set by the 2050 European Green Deal.Thus,several programmes for the major network renewals and the construction of safe,resilient,and efficient high-speed(HS)lines have been implemented.In this scenario,some construction solutions have been introduced to enhance the durability and functionality of the railway infrastruc-ture,particularly for the ballasted track one.Among these design techniques,the asphalt or bituminous sub-ballast has emerged as a proven technology capable of improving the rail-way performance and durability.Derived from the road construction approach,asphalt sub-ballast has been used in the European HS and high-capacity(HC)lines since the 1970s,providing both structural and functional benefits.This article offers a critical review of the current knowledge on the asphalt sub-ballast applications,highlighting its technical characteristics and long-term performances.Functional,structural,and economic advan-tages have been assessed and analyzed based on laboratory scale and on-field experiences.Experimental data indeed confirm the effectiveness of asphalt sub-ballast in improving the track stability and load distribution,in providing better water drainage and in reducing fatigue induced phenomena.These enhanced properties lead to lower maintenance costs and operations,particularly those related to ballast tamping,as well as to an extended ser-vice life of the whole infrastructure.From the circular economy perspective,the re-use or recycle of wastes and by-products in these mixes amplifies the cost-benefit ratio,also improving their sustainability.
