Rail Integrity Research Articles

Application of Surface Ultrasonic Waves for Detection of Contact Fatigue Cracks in the Rail Surface

The integrity and durability of rails plays a key role in train safety. However, the interaction of the rail head surface with the wheels of the rolling stock leads to high damage to these areas. The surface of the rail head is subject to the greatest damage, in which fatigue cracks develop on the surface with subsequent development. Timely detection of fatigue cracks in the rolling surface is possible using the ultrasonic technique using surface waves. To do this, the work investigated the sensitivity of a surface ultrasonic wave to obstacles in the surface of rails in the form of extended grooves, notches of finite length and known depth, as well as real cracks. The studies were carried out using the pulse-echo method at frequencies of 1.25, 1.8, 2.5, 4 MHz. Research has shown that surface waves are sensitive to surface fatigue cracks. The amplitude of the reflected pulses depends on the wavelength and the depth of crack propagation. The influence of the distance to fatigue cracks and the orientation angle of the transducer relative to the rail axis on the sensitivity of the surface wave to these defects was also studied. The results obtained allow us to conclude that the use of surface ultrasonic waves makes it possible to detect fatigue cracks in the crack surface. Thus, the use of the pulse-echo technique and surface wave converters makes it possible to detect contact fatigue cracks in the rail head, which can be used to eliminate them in a timely manner. The determination of their depth by amplitude is influenced by many factors, which are difficult to take into account in real conditions.

Imaging localisation of damages on switch rail foot based on laser ultrasonic testing

ABSTRACT The corrosion on the switch rail’s foot may easily lead to rail breakage. Laser ultrasound detection is often used to assess the integrity of rails. Nevertheless, the inadequate photoacoustic conversion efficiency and vulnerability to surface interference of the entirely non-contact laser ultrasound result in a diminished signal-to-noise ratio (SNR), hence impeding the efficient detection and analysis of minor damages in the rail. This work demonstrates piezoceramic material lead zirconate titanate (PZT) wafers in conjunction with a pulsed laser to create a sensor array capable of accurate array image inspections. The PZT sensor arrays are manufactured in a flexible format that may be easily installed and altered to complicated geometries. Pulsed lasers are used to achieve dense and high-frequency array excitation. This study proposes a novel probabilistic picture location identification strategy by merging the variable mode decomposition algorithm based on parameter optimization (PVMD) and the principle component analysis (PCA) algorithm. The aim is to enhance the SNR and increase the accuracy of damage findings. Simulation and experimental tests have demonstrated the accuracy of the suggested mechanisms and algorithms in identifying damaged regions.

Effect of normalizing treatments on microstructure and electrochemical corrosion properties of U75V-welded joints in an acidic environment

Corrosion poses a significant threat to the structural integrity of steel rails, especially in an acidic environment. In this study, we evaluate the corrosion properties of U75V-welded joints using potentiodynamic polarization curves, electrochemical impedance measurements, and corrosion morphology studies under simulated acidic conditions. Compared to non-normalized joints, the normalized joints exhibit a higher self-corrosion current (4.65 × 10−5 A/cm2) and a more negative self-corrosion potential (−0.56919 mV). The smaller and more uniform grain size obtained after normalizing provides multiple active sites on the surface for polarization reactions. Furthermore, owing to significant erosion caused on the rail surface by the acidic solutions, normalizing treatment enhances the passivation effects on the surface, resulting in increased corrosion resistance (221.96 Ω cm2). Our findings provide insights into the impact of normalizing treatments on the corrosion mechanism of U75V rail joints under acidic conditions.

Rail Surface Integrity Analysis in Laboratory

This study aims to assess the effect of grinding on the surface integrity of rail materials. Two grinding processes (preventive and corrective) were employed along with the corresponding usage scenarios throughout a series of tests. For the purposes of testing, samples in the form of discs were utilised to assess the surface integrity of rails. Testing initially involved introducing some wear on the discs followed by the appropriate grinding process and then further testing to monitor the disc’s performance. More specifically the preventive grinding was utilised in a scenario where rail discs endured normal usage prior to grinding and corrective grinding process was employed in rails discs that had been run for extensive cycles (2.5 times longer compared to normal usage) to generate significant wear before grinding. After the maintenance process all the specimens were further examined to assess their post-grinding performance. The experiments revealed that the aggressive single grinding pass methodology followed in a corrective maintenance approach could lead to undesirable results as the increased heat input, high surface roughness as well as the initial cracks from the prolonged pre-grinding running period could have an adverse effect on the RCF life. This was demonstrated by an almost triple wear rate compared to the “normal” usage scenario during the post-grinding testing.

Rail integrity control system with closed loop approach

Rail systems have been used for transportation and carriage purposes since the beginning of the 19th century and are still an important means of transportation today. This transportation method is actively used in densely populated Asian countries, especially in America and European countries. According to data from the National Safety Council (NSC) in the United States, rail travel is indeed one of the safest modes of transportation, second only to air travel. NSC reported that in 2019 rail fatality rates were 0.31 deaths per billion passenger miles, while the death rate for air travel was only 0.061 deaths per billion passenger miles. However, this does not mean that serious accidents do not occur. Moreover, the cause of the majority of these accidents is derailment caused by line deterioration and breaking of rails. According to technical data from the Federal Railroad Administration (FRA), in 2020 there were 1,601 accidents caused by track issues, including rail cracks and deterioration. These statistics highlight the importance of regular road maintenance and inspection to ensure the integrity of the railway and prevent accidents caused by road problems. To date, many studies have been carried out to control and ensure the integrity of the rails. In our study, the main aim is to provide a system that will verify that there is no crack in the rails, and otherwise inform the machinist. Furthermore, this study does this verification by dividing the rail structure into small blocks and checking whether the circuit is completed with the electric current it provides over the train. Thanks to this easy-to-apply system, the deformations on the rails can be easily detected pointwise and the number of fatal accidents can be reduced.

Development of Sustainable Integrated Transit Area in Gorontalo Province, Indonesia

Transportation integration is the integration of air, rail and land transportation modes with the aim of improving transportation performance more efficiently and effectively. The development of transit areas is important in order to realize a sustainable transportation system. Isimu Terminal in Gorontalo Province is a gateway to access to various modes of mass public transportation that serve inter and intra-provincial transportation. This research aims to evaluate the existing conditions of the Isimu terminal based on the evolution of the implementation of transit area development according to the categories: seamless mobility, sustainable neighborhood and optimum growth. This research is qualitative deductive. Primary data was obtained through in-depth interviews with station users and direct observation. Secondary data is obtained through institutional surveys to relevant parties. The result the integration of services between Djalaludin airport and Isimu terminal does not seem to be optimally connected and the loading and unloading of goods outside the terminal is visible. However, this area has the prospect of functioning as an intermodal connectivity node with the planned infrastructure development of the train station, Djalaludin airport, and Isimu terminal, and as further suggestions this area can be developed into an integrated transit area and transhipment node.

Constructing the Frontier: Russian-Chinese Trade as a Factor in the Modernization of the Far East at the Turn of the 19th and 20th Centuries

The article delves into the development of the transport and logistical infrastructure on the Far Eastern frontier of the Russian Empire during the late 19th and early 20th centuries. Throughout the period under study, challenges that emerged in the trade relations between Russia and China led to the creation of a new freight transport system for Russian-Chinese trading. This system proposed the integration of rail and maritime communication, with a sea port acting as the central logistical hub. This vision materialized with the construction of Russian railways in Manchuria, the leasing of Port Russian Dalian on the Liaodong Peninsula, and the initiation of maritime shipping by the China Eastern Railway Company. The article aims to systematically investigate the foundational concepts and the actualization of each segment of this new infrastructure. The research uncovered that the railways, sea port, and maritime shipping orchestrated by the Russian Empire in the Far East were viewed as cohesive elements of a unified trade and transport corridor. This corridor’s primary goal was to forge an effective linkage with the Pacific region. The data assessed in the study indicates that the Chinese ports and market stood as the foremost objectives for Russia’s geoeconomic pursuits in the Far East. In conclusion, the study underscores the importance of these novel infrastructural developments in the frontier modernization of the Far Eastern boundary shared by Russia and China.

Real-Time Surveillance of Rail Integrity by the Deployed Telecom Fiber Infrastructure

Real-Time Surveillance of Rail Integrity by the Deployed Telecom Fiber Infrastructure

КОНТРОЛЬ ЦЕЛОСТНОСТИ РЕЛЬСОВЫХ НИТЕЙ ПРОТЕКАЮЩИМ ТОКОМ

Violations of the integrity of rails on railway sections pose a serious threat to traffic safety, cause accidents and wrecks, lead to significant economic damage and human casualties. The integrity of rails is controlled by flaw detection methods, as well as by a special mode of operation of rail circuits due to the signal current flow around track circuits. The widespread use of AC rail circuits which reliably perform the control mode made it possible to organize a simple method of integrity control over a significant length of railway lines. The complexity of maintenance and low reliability of track circuits, in turn, led to emergence of alternative technical solutions for monitoring the vacancy of railway sections. However, these solutions are not able to control the integrity of rails and prevent elimination of track circuits. On the other hand, the joint use of continuous monitoring of rails and low-maintenance solutions for monitoring the vacancy of track sections will ensure reduction in operating costs with a constant level of traffic safety. The article analyzes technical solutions for monitoring the integrity of rails due to continuous current flow. The maximum length of the contour formed by two rails is set to control the integrity of the rails. The prospects of solutions for monitoring the integrity of rails based on the electrical circuit formed by rails and a cable running along them are shown.

GIS Based Procedural Modeling in 3D Urban Design

Traditional urban design is time-consuming and laborious. We propose a computer-generated architecture (CGA)-based workflow in this work, with the goal of allowing designers to take advantage of a high level of automation. This workflow is based on procedural modeling. A three-step CGA rule was applied to implement 3D urban procedural modeling, (1) parcel subdivision and clustering, (2) building extrusion, and (3) texture mapping. Parcel subdivision and clustering is the key step of layout modeling, giving the modeler flexibility to adjust the placement and size of the inner building lots. Subsequently, a land-use-based combination of eight common building types and layouts was used to generate various urban forms for different urban functional zones. Finally, individual buildings were decorated by creating texture maps of a planar section of the building facade or, alternatively, decomposing facades into sets of repeating elements and texture maps. We employed the proposed workflow in the H-village urban redevelopment program and an air–rail integration zone development program in Guangzhou. Three design proposals were generated for each project. The results demonstrated that this workflow could generate multiple layout proposals and alternative facade textures quickly and, therefore, address most of the collaborative issues with its analysis functions, including a flexible adjustment mechanism and real-time visualization.

Beyond Start and End Points: Accessibility of Railway Stations on a Multi-Spatial Scale

This paper presents results and policy implications from RAISE-IT, an EU Connecting Europe Facility (CEF) funded project. It examines the integration of long-distance rail with local and regional transport networks at key urban nodes along the Rhine-Alpine Corridor, one of the nine Trans-European Core Network Corridors (CNCs). It is crucial to foster seamless and suitable passenger transport solutions to achieve emissions goals and support the decarbonization process. Consequently, the whole travel chain needs to be considered and good interconnections with other transport modes are needed. For this reason, RAISE-IT explored multi-spatial scale accessibility. It considered three spatial scales (local, regional, and corridor-wide) and looked into multiple travel distances and needs along the corridor for accessing and minimizing the gap between highly and less accessible railway stations with reference to multi-scale travel patterns. This approach revealed overlapping issues between cross-regional and local decision makers and facilitated opportunities to discuss challenges and areas for improvement. The results formed the basis for guidelines on how to improve the accessibility of urban nodes and the quality of services and connections provided at railway stations. This paper discusses potential transferability aspects and recommendations for policy implications from RAISE-IT for railway stations and urban nodes in other CNCs.

Workability of a multiple-gateway airport system with a high-speed rail network

The surge in inbound tourists has caused severe congestion at the primary airport in Japan and a few other Asian countries. Certain researchers have argued that the integration of air and high-speed rail (HSR) transport can be used to transfer passengers from a congested airport to a noncongested airport. However, they have considered an idealistic situation instead of an actual situation. Therefore, actual data must be analyzed to determine a workable policy for establishing a useful system with HSR. This study discusses practical policies for maintaining a workable air–HSR system to handle the surge in international tourists based on the Tokyo metropolitan area. We carry out scenario studies by applying the bilevel air transport model. We consider three types of gateway candidates and fare support policies for air–HSR connecting services. In addition, we examine the scenarios of runway capacity expansion at Haneda Airport (HND). The results show that the application of a policy to an airport with air–air and air–HSR connecting services can provide the desired workability and serve as a substitute for capacity expansion at HND. However, as compared to capacity expansion at HND, most carriers lose profits when a secondary gateway works appropriately.

Combined effect of rolling contact fatigue and corrosion on structural performance of rails

ABSTRACT An accurate structural assessment of rails under combined effect of fatigue and corrosion prevents a phenomenal disaster, also saves millions of dollars and people’s lives. Recent studies which are proposed to simulate a precise model fail to take into account the different underlying mechanism for rail corrosion. The current study presents a numerical procedure to investigate crack initiation under combined effect of fatigue and corrosion. A three-dimensional (3D) finite element model (FEM) which accounts for rolling contact stresses due to wheel-rail contact loads is developed. Then, stress distribution is used in a MATLAB code to estimate the fatigue crack initiation life. The advantage of the proposed model is considering the combined effect of rolling contact fatigue and corrosion on structural integrity of rails. This model is applied to a case study of rail assessment in Melbourne, Australia. The cracks orientations and locations which were based on the FEM results were in good agreement with the field observations.

Probing the effect of abrasive grit size on rail grinding behaviors

Three grinding wheels were developed via regulating the abrasive grit size (F10, F16, F30), and their performances are evaluated by a self-designed grinding device. The surface integrity of grinded rails and material removal mechanism were discussed. The results illustrate that the abrasive grit size has a significant effect on the residual stress, surface topography, oxidation and crystal structure of grinded rail surfaces. With the decrease of abrasive grit size, the grinding mechanism gradually changes from rubbing and ploughing to cutting operation. Better surface integrity can be acquired using finer abrasives because of the lower roughness, lower magnitude of residual stress and thinner white etching layers (WELs). And the WELs with nanocrystalline structure could yield the pre-fatigue and abridge the RCF life of rail.

Improving Synchronization in an Air and High-Speed Rail Integration Service via Adjusting a Rail Timetable: A Real-World Case Study in China

Air and high-speed rail (AH) integration services are gaining ground with the development of the high-speed railway and airline industries. A well-designed feeder train timetable with good synchronization is of great significance in an AH integration service, because it can improve the connectivity at transfer nodes and offer more opportunities for intermodal passengers to travel. In this study, we propose a multi-objective model of a feeder railway timetable problem in an AH integration service to improve synchronization. The aims of the optimization model are to maximize the number of synchronizations and the coverage of synchronized flights, as well as to minimize the transfer penalties of passengers. We focus on a scenario of a partial subnetwork in which one direction of a two-direction railroad line with one transfer station is considered. The model is applied to Shijiazhuang Zhengding International Airport, China. The results illustrate the effectiveness of the approach developed in the paper.

Microstructure and Mechanical Properties of Continuous Welded 50N Rail

Rails are subjected to repeated stresses due to wheel-rail contact during train service. Rails under stress conditions undergo microstructural changes, and these cause degradations of the structural integrity and lifetime of rails. In this study, three different rails (newly-manufactured rail, newly-manufactured headhardened rail, and worn (used) rail) were compared to examine the effects of heat treatment and repeated wheel-rail contact stress on the microstructure and mechanical behavior of continuous welded rail. The crystal structure, constituent phase distribution, tensile property, and hardness were investigated at various locations along a cross section of the rails. All three rails consisted of a mixture of BCC and FCC crystal structures as a majority phase with a very small amount of cementite (Fe3C) as a minor phase. Rietveld analysis revealed that the weighted fractions of the BCC crystal structure were approximately 74%, 64%, and 85% for the new rail, head-hardened rail, and worn rail, respectively. While the web and foot areas of the three rails showed no significant differences in mechanical properties, the railheads of the three rails revealed much higher yield strength, tensile strength, and hardness. The highest tensile strength and hardness were measured at the railhead in the head-hardened rail, and were attributed to the evolution of the bainite phase, generated by additional heat treatment. The higher mechanical strength of the railhead of the worn rail is thought to have resulted from a combination of work hardening and smaller lamellar spacing of the pearlite phase, induced by repeated wear processes during train operation. (Received September 30, 2019; Accepted November 4, 2019)

CO2 emissions mitigation potential of buyer consolidation and rail-based intermodal transport in the China-Europe container supply chains

Abstact Freight transport is an increasingly important contributor to global warming. With the projected development of international trade, finding the most energy efficient ways of service intercontinental trades is a key challenge. China-Europe containerized trades are among the most important in this setting. The typical structure of the supply chains associated with this trade is that containers are stuffed in China and then cargos are subsequently cross-docked at major European logistics hubs or distribution centers in the destination countries for further road transport to the final retailing points. This solution may not be optimal from an environmental perspective. To pursue an increasingly sustainable supply chain solution, early movers in the market have adopted an alternative solution that is characterized by upstream buyer consolidation and downstream rail-based intermodal transport. This paper develops a set of mathematical models for analyzing the environmental saving potential of such alternative solutions, encompassing relevant energy use and energy mix data of all the legs and nodes in the supply chains. The empirical analysis is based on a case obtained from a Swedish retailer with a chain of retailing points in Scandinavia and Poland. From an activity-based approach, our findings suggest that upstream buyer consolidation may facilitate the integration of rail and road transport in the destination country, increase container utilization, replace 20-foot containers by 40-foot containers and eliminate the extra de-/re-consolidation activity in the traditional solution, thereby reducing CO2 emissions of the supply chain. This, more efficient supply chain solution, may facilitate a modal shift in the downstream part of the supply chains, which may be attractive to logistics providers, retailers and customers in search of ways of curbing CO2 emissions. The models and analytical framework developed may also be used by practitioners and researchers for analyzing other alternative supply chain designs.

Ultrasonic guided wave focusing in waveguides with constant irregular cross-sections

As essential components of a high-speed railway system, switch rails can be easily damaged by sophisticated operating conditions. Therefore, precise online detection for switch rails is necessary. Methods based on ultrasonic guided waves are ideal candidates for structural integrity of the switch rails, which are natural waveguides with irregular cross-sections. However, energy decentralization in the wave propagation severely restricts detectability. Phased array systems have been developed and implemented to steer and focus acoustic energy in waveguides of ordinary cross-sections such as pipes and plates. This paper proposes a method for ultrasonic guided wave focusing in waveguides with constant irregular cross-sections. We analyzed the characteristics of the guided waves generated by partial loadings based on a semi-analytical finite element method (SAFEM). An algorithm was developed for calculating the amplitude weights and time delays required to modulate excitation signals. Two coefficients were defined to evaluate the wave focusing results, namely the half area coefficient (HAC) and half energy coefficient (HEC). Numerical simulations to verify the proposed method were carried out for a switch rail base with a constant irregular cross-section. The results demonstrate that the guided acoustic beam has been effectively steered to focus at the pre-determined locations with enhanced acoustic wave energy. Furthermore, the influence of various factors on guided wave focusing was studied. Excitation signals of low center frequencies with narrow bandwidths are recommended for ideal focusing results.

Особенности системы управления движением поездов на высокоскоростной магистрали «Москва–Казань–Екатеринбург»

Objective: To consider the requirements for the train control system (SUDP) at “Moscow-Kazan-Yekaterinburg” high-speed network (VSM). To develop system-wide requirements for SUDP, including the selection of the structure and composition of subsystems. Methods: Computer-based interlocking with contactless control of vehicles should be applied at the stations as the main means for train traffic control. Vocal frequency track circuits were determined as the major means for free and busy status control of track at stations and blocks, an information channel giving an update of a track ahead, and the means for a rail integrity test. Stationary equipment for train collision avoidance via radio channel is to provide train traffic with speeds up to 400 km/h, multiple-aspect ALS-YEN (integrated continuous automatic cab signaling system), depending on control technology with speeds up to 250 km/h and ALS (automatic locomotive signaling system) – up to 160 km/h. Results: The issues of providing reliable and safe functioning of SUDP were considered, as well as liveness and interoperability. Practical importance: Control system realization in the suggested configuration with combined data communication via radio channel and conventional ALS and ALS-YEN facilities will make it possible to provide train traffic collision avoidance backup, as well as interoperability with high-speed transport lines. Keywords: High-speed network, train control system, centralized traffic control, computer- based interlocking, train traffic collision avoidance, radio-block center.

Air and HST Multimodal Products. A Segmentation Analysis for Policy Makers

Different solutions for the integration of high-speed rail (HSR) and air transport could be implemented, ranging from very basic integration to more sophisticated systems that include ticket and handling integration. This paper uses two statistical techniques, name cluster analysis and discrete choice models in order to investigate how different market segments have a determining influence in being more proactive to change to HSR for the second leg in multimodal trips. A discrete choice experiment is conducted to better understand passengers’ preferences. We obtain a number of clusters and estimate flexible choice models, taking into account the panel nature of stated preference data. We obtain a range of willingness-to-pay values for service quality attributes, finding results that can be used to infer policy conclusions about the real attractiveness of the Air-HSR integrated alternative. In this respect, clusters and schedule coordination, which reduces connecting time, are crucial to explain HSR attractiveness.