Railway Engineering Research Articles

The friction modifier performance in twin-disc tests using discs of the same microstructure and hardness

Friction management in the wheel-rail interface has received great attention from railway engineering in recent years, mainly due to the possibility of reducing wheel and rail wear. The addition of greases, lubricants and friction modifiers on the track has increased in the main railroads of the world. However, studies demonstrating the effect of applying friction modifiers are mainly carried out by manufacturers. To evaluate the action of the friction modifier, laboratory tests are less expensive tools and can give an indication of the benefit of the application. Thus, in this work, dry and wet twin-disc tests were carried out using discs with the same microstructure and hardness, evaluating only the action of the friction modifier. It was noted that the retentivity of the friction modifier had increased with the distance covered in the test. These results would contribute to increase the distance between applicators on the railway track and promoting a lower volume of product per distance traveled. The addition of a friction modifier also reduced the traction coefficient throughout the test, which contributed to lower wear of the disc. The friction modifier induced Rolling Contact Fatigue - RCF cracks with greater depth and length due to hydro pressurization action. However, the addition was still beneficial because the wet condition keeping the friction at smaller values, the crack propagation takes longer to occur.

“Materials of the School of ‘Mathematical and Navigational Sciences’ under the jurisdiction of the armory chamber” from N. P. Durov’s collection as a historical source

The School of Mathematical and Navigational Sciences, the first specialized technical educational institution in Russia, was founded on the initiative of Peter the Great in Moscow in 1701. Subsequently, the Maritime Academy in St. Petersburg (1715) was set up, based on the School’s Navigators’ Classes. Most of the School’s documents were lost during the fire in the Naval Cadet Corps in 1771. A set of manuscript documents bound together, comprising the Navigation School’s bookkeeping documentation, has been preserved in the personal fonds of N. P. Durov (1831–1879), professor at the Institute of the Corps of Railway Engineers (St. Petersburg) and historian of science and technology, deposited at the Russian State Library’s Manuscript Department. This manuscript has so far remained unpublished and little-known to researchers. Durov was a renowned bibliophile and collector of manuscripts and books. Many unique handwritten materials ended up in his library after the acquisition of a part of the book collection that belonged to a collector and amateur archeographer A. I. Sulakadzev. However, as our research proved, Durov obtained these Navigation School’s manuscript documents from the home library of the writer B. M. Fedorov. After Durovʼs death, these documents were purchased by the Moscow book dealer V. V. Gautier and subsequently acquired from him by the Library of the Moscow Public Museum. This manuscript is an important source on the history of the creation and early years of the Navigation School. It includes petitions to the Tsar from its future students and the documents of both the School and the Armory that contain information about the educational process organization and the first naval cadets’ everyday life.

Optimizing Railway Tribology: A Systematic Review and Predictive Modeling of Twin-Disc Testing Parameters

Twin-disc testing is crucial for understanding wheel–rail interactions in railway systems, but the vast array of testing parameters and conditions makes data interpretation challenging. This review presents a comprehensive analysis of the twin-disc literature experimental data, focusing on how various parameters influence friction and wear characteristics under stationary contaminant conditions. We systematically collected and analyzed data from numerous studies, considering factors such as contact pressure, speed, material hardness, sliding speeds, adhesion, and a range of contaminants. This research showed inconsistent data reporting across different studies and statistical analyses revealed significant correlations between testing parameters and wear rates. For sand-contaminated tests, a correlation between particle size and flow rate was also highlighted. Based on these findings, we developed a simple predictive model for forecasting wear rates under varying conditions. This model achieved an adjusted R2 of 0.650, demonstrating its potential for optimizing railway component design and maintenance strategies. Our study provides a valuable resource for researchers and practitioners in railway engineering, offering insights into the complex tribological interactions in wheel–rail systems and a tool for predicting wear behavior.

Study on the Degradation Model of Service Performance in Railway Steel–Concrete Composite Beams Considering the Cumulative Fatigue of Steel Beams and Studs Based on Vehicle–Bridge Coupling Theory

The steel–concrete composite beam, as a structural form that combines the advantages of steel and concrete, has been applied in railway engineering. However, with the increase in railway operation time, the degradation pattern of the service performance of steel–concrete composite bridges remains unclear. This paper proposes a method for calculating the long-term service performance of railway steel–concrete composite beams, considering the cumulative fatigue damage of steel beams and studs, based on the vehicle–bridge coupling theory and Miner’s linear cumulative damage criterion. The proposed method is validated using measured data from an in-service steel–concrete composite railway bridge with spans of 40 + 50 + 40 m. The calculated mid-span vertical displacement and the first two natural frequencies of the composite beam deviated from the measured results by only 2.1%, 7.7%, and 9.5%, respectively. The research results can provide a basis for extending the service life of composite beams and preventing the occurrence of safety accidents.

Experimental and numerical investigations into torsional-flexural behaviours of railway composite sleepers and bearers

Abstract Fibre-reinforced foamed urethane (FFU) composite sleepers and bearers are safety-critical components installed in complex railway switches and crossings. Not only does they need to provide vertical track support, the composite sleepers and bearers must also endure longitudinal and lateral actions stemming from complex wheel and rail interactions. In reality, the railway bearers at crossing noses are susceptible to coupling torsional-flexural loading. The complex non-linear behaviours have never been investigated numerically nor experimentally. It is thus necessary to comprehend torsional-flexural behaviours of FFU composite sleepers and bearers through finite element and experimental approaches. 3D finite element modelling of FFU composite beams have been established to predict the non-linear coupling behaviours. Three specimens of FFU beams have been prepared for robust experiments under each load case. Our studies exhibit excellent agreement between numerical and experimental results. The ductile failure behaviours (post yield point) have been observed from the experiments. Considerable effects of load eccentricity on the flexure–torsion behaviours of the composite members can also be noted. In addition, the load-eccentricity curves have been identified to portray the non-linear behaviour of the railway components under coupling flexural and torsional loadings. The new insights considering their load–displacement relationships, modes of failure and damage, flexural and torsional interactions are the precursors for railway engineers to design and adopt FFU composite sleepers and bearers in practice where complex wheel/rail interface generally causes coupling torsional and vertical loading conditions.

Dynamic Modeling and Analysis of Multi-Span Timoshenko Beams Under Moving Loads

Dynamic response analysis of multi-span beams is one of the important topics in the field of highway and railway engineering, which provides valuable guidance for the design, operation and maintenance of multi-span bridges. It is worth considering how to calculate the dynamic characteristics of multi-span beams quickly and conveniently. In this study, an effective analytical method is developed for the dynamic modeling and investigations of multi-span Timoshenko beams under moving loads by employing the assumed mode method (AMM). Based on Hamilton’s principle, the equation of motion of the Timoshenko multi-span beam subjected to moving loads is formulated and the natural frequencies are calculated. A comprehensive investigation is conducted on the dynamic responses of the multi-span Timoshenko beam considering different factors, including the length-to-thickness ratio, disorder degree, arrangement order, number of spans and related parameters of moving loads. In addition, the influence of the interval and velocity of the moving load series on the dynamic responses, including displacement, velocity and acceleration of the multi-span beam, are analyzed in detail. The theoretical calculation results of multi-span Timoshenko beams under moving loads are compared with numerical results obtained from ANSYS software, and the results are in good agreement. This demonstrates that the developed method, which utilizes the AMM to analyze the dynamic characteristics of multi-span beams subjected to moving loads, significantly simplifies the calculations and is well-suited for practical engineering applications.

Research on information extension of mountainous rack railway engineering based on IFC standard

In response to the practical demands for data sharing and exchange in the field of rack railway systems engineering, as well as to address the gaps in the rack railway domain within the framework of the IFC4 standard, we extend and define the rack railway domain through entity extension and custom attribute sets. By utilizing the ongoing construction of the Dujiangyan to Mount Siguniang Railway as a case study, we validate the utility of this IFC extension and modeling approach. Leveraging IfcOpenShell, we incorporate the extended data content into the generated IFC file. We present a process for extension tailored to the characteristics of rack railway engineering. This study aims to provide broader information support for the digital construction of track structures in the design phase of rack railway engineering and to facilitate more efficient data exchange and sharing.

A robust and fail-safe semi-active vertical damper to improve ride comfort

In recent years, the technical progress in railway engineering has led to the integration of electronic elements in suspension components that once were purely mechanical. Many studies have been carried out, developing active and semi-active suspensions. Among these, semi-active suspensions are particularly attractive due to their simpler design compared to fully active ones. In this context, this paper proposes a semi-active vertical damper to be implemented on the secondary suspension stage of rail vehicles. A prototype is developed by modifying a pre-existing passive damper through the addition of an external servo-valve which manages an additional by-pass channel between the compression and rebound chambers. The prototype is characterised on a dedicated test rig. A reduced vehicle model is then developed as the starting point in developing a sliding mode controller to manage the semi-active feature of the damper. A time-varying sliding surface containing the state of the system and car body accelerations is proposed. Finally, the damper prototype is tested on a hardware-in-the-loop test rig, focusing the experimental campaign on quantifying the damper performance, the evaluation of the controller robustness and a failure analysis to study the behaviour of the proposed solution even in the case of unexpected failures.

Routing and scheduling of trains and engines in a railway marshalling station yard

In a busy railway marshalling station, train and engine traffic management in the receiving/departure yard plays a crucial role in efficient and stable operations. Traditionally, a track assignment problem (TAP) is solved to assign tracks to trains for berthing at a receiving/departure yard. However, the TAP does not encompass shunting operations in the yard (e.g., engine replacement and train disassembly), which can result in additional scheduling challenges for dispatchers and route conflicts between operations. This paper investigates a train and engine routing and scheduling problem (TERSP) in a receiving/departure yard of railway marshalling stations, which involves simultaneously assigning routes and scheduling route-setting start times for both train and shunting operations to be conducted in the yard. By introducing the concepts of task, activity, and pattern, we transform the original problem into assigning pre-generated patterns incorporating both route and route-setting start time alternatives to activities. The transformed problem is formulated into a compact binary integer linear programming model with a linear number of constraints and the objective of minimizing the total time deviation of all involved tasks. An improved technique that relies on listing all maximal (bi)cliques in a constructed graph is designed to effectively model the time coherence and track section occupation constraints. A heuristic that gradually expands the patterns for the identified key activities by adding more start time alternatives is applied to remedy an infeasible model caused by potential route conflicts. In addition, a rolling horizon algorithm that decomposes the original problem into consecutive smaller stages using either a time-rolling or a train-rolling rule is developed to efficiently solve instances. Finally, numerical experiments based on the physical layouts and real timetables of a receiving yard and a departure yard of a large marshalling station in China are conducted to assess the performance and applicability of our proposed approaches. The results demonstrate that our approaches typically find (near-)optimal solutions within several minutes for the investigated instances by simultaneously addressing different classes of yard operations and resources.

Enhanced multi-scenario running safety assessment of railway bridges based on graph neural networks with self-evolutionary capability

Accurate and efficient safety assessment for train-bridge coupled (TBC) systems is paramount in railway engineering. Traditional neural networks, though efficient and apt for real-time applications, falter in generalizing to untrained engineering scenarios. Addressing this gap, this study introduces a novel graph isomorphic network (GIN) endowed with the self-evolutionary capability, specifically tailored for seismic safety assessments across various scenarios in TBC systems. Initially, the study devises a graph representation method that adeptly encapsulates the structural complexities of TBC systems into graph data. This data is subsequently processed by the enhanced GIN model, refined for optimal alignment with engineering structures. The unique self-evolutionary mechanism of the GIN model equips it to interpret and predict the characteristics of new engineering scenarios, leveraging the extant training data. Empirical evaluations reveal the proposed GIN model's superiority in assessing known scenarios and its exceptional ability to generalize to new ones, outperforming traditional neural networks. Additionally, this study underscores the GIN model's potential applicability across diverse engineering fields.

Constitutive modelling of a dry sand–structure interface under high-frequency vibration with a constant normal load

Sand–structure interfaces undergo strength loss and volume contraction under high-frequency vibration, potentially compromising the performance of underground structures in high-speed railway engineering. However, an appropriate method for quantitatively characterizing the behaviour of the sand–structure interface under high-frequency vibration is currently lacking, impeding the advancement of related design methods. In this work, the primary deformation and strength characteristics, such as the evolution of shear stress and volumetric strain, of the dry sand–structure interface under high-frequency vibration are summarized via a modified direct shear apparatus under a constant normal load. The concept of “vibro-induced virtual pore pressure” is subsequently introduced to modify the expressions of the critical state, yield, and bounding surfaces. The relationships between vibro-induced volume contraction and the vibration stress amplitude and state parameters are also established. Ultimately, a constitutive model describing the behaviour of the dry sand–structure interface under high-frequency vibration is formulated within the frameworks of critical state soil mechanics and bounding surface plasticity. The model comprises 14 parameters, all of which can be calibrated via laboratory experiments. Through comparison with experimental observations, the model is found to accurately simulate the key behaviours of the dry sand–structure interface under both static and high-frequency vibration conditions with a constant normal load, effectively reflecting the influence of the density, normal stress, and vibration stress amplitude of the sample.

The epic of the Baikal-Amur Mainline is the fate of millions. On the 50th anniversary of the start of construction

The Baikal-Amur Mainline is one of the most ambitious and controversial Soviet projects on the sociopolitical and historical trail of perception. The proposal to build a new railway north of the Trans-Siberian Railway was put forward at the beginning of the 20th century. The idea was approached in the 1920s and 1930s. Surveys were conducted, and construction began on one of the sites, which was interrupted by the Great Patriotic War (World War II). Moreover, during the war years, the upper structure of the track and a number of engineering structures were dismantled on the constructed site, which were used for the construction of the extremely important rockade railway in the Stalingrad area, which played a significant role in supplying Soviet troops during the Battle of Stalingrad. The interest in the construction of the BAM of the Soviet leadership in the 1960s and 1970s arose again in the context of an aggravation of the political situation — the complication of relations between the USSR and the People’s Republic of China. However, already during this period, the question was reasonably raised not only about the political, but also the economic strategic significance of the project from the perspective of the country’s development prospects, the development of natural resources in this region, the development of transport links between the European, Siberian, and Far Eastern territories of the state. In the period after the collapse of the USSR, the BAM construction project, not without the influence of those who were under Western influence in the country’s leadership circles, was classified as erroneous, extremely costly, economically and socially unjustified. Today, in society, the state, under the influence of many factors of recent years, there is an understanding of the importance of completing and developing the BAM construction project. This project has played a big role in the lives of millions of people, many organizations and institutions. Among them is the Leningrad Institute of Railway Engineers — today the St. Petersburg State University of Railways of Emperor Alexander I, whose students, graduates, scientists and specialists have been involved in various forms in the construction of the Baikal-Amur Mainline for half a century.

You are remembered by grateful memory, Mr. Betancourt

The article covers the life and certain episodes of the activities of Augustin Betancourt (1758–1814), an outstanding engineer, scientist, architect, teacher, and statesman of Spain and Russia, in Russia. Arriving in Russia at the personal invitation of Emperor Alexander I, and being in the Russian service from 1808 to 1824, A. Betancourt left a notable mark in the history of engineering and construction, in the development of industry and transport of the Russian Empire, and formation of engineering education in the country. Based on the sources, including those of the XIX century, the article provides information on the main projects implemented by him in Russia, offers characteristics of the relations between Augustin Betancourt and Emperor Alexander I, and other statesmen of that epoch, and reveals some personal and psychological peculiarities of behaviour of the engineer and scientist. An attempt is made to study the reasons for the tsar’s disfavour of Augustin Betancourt and his resignation from government posts. The article describes the conspicuous merits of A. Betancourt, his contribution to speeding up the industrial revolution in Russia, gives the main facts related to the special role of the scientists of Emperor Alexander I St. Petersburg State Transport University (PGUPS),the successor of the Institute of the Corps of Railway Engineers (IKIPS), organised by Betancourt, and the Betancourt’s Legacy International Scientific and Educational Project held since 2015 and the annual Betancourt International Engineering Forums dedicated to the development of higher engineering education in the world. This article is dedicated to the memory of Augustin Betancourt and is published in the year of the 200th anniversary of his passing on July 26 (14), 1824.

The Radical Instability of the Present

This article uses Muhammad Khudayyir's novel-memoir Basrayatha as a loose theoretical framework to explore the ramifications of a not-yet-built infrastructure, tracing how late Ottoman officials, intellectuals, and engineers thought about the not-yet-built Baghdad Railway and the land it was meant to transform. Examining how railway boosters, Ottoman officials, and engineers located the region's “truth” and future in a lost past, the article argues that making this connection depended on cultivating material and discursive absence in the “ruined” present. The article highlights how practical techniques for making place into the kind of “space” where homogenous time could march forward coexisted with grandiose visions of future prosperity inspired both by the distant past and by the present of places like Egypt. In contrast to analyses that have emphasized the uncertainty of past and/or future, this article argues that the present was the problem because it was fundamentally unknowable—and that this very unknowability allowed railway advocates to absent the extended present of ruin from an idea of the truth of Iraq, instead drawing a direct line between past and future prosperity.

Rail crack identification of in-service turnout through Bayesian inference

In-service railway turnout, suffering from multi-factor coupling of operational and environmental loadings and special wheel–rail interaction, is prone to structural damage. The paper aims to develop a Bayesian damage identification method for crack-alike damage of the turnout rail under uncertainties. It consists of three core parts, including a damage index (DI) constructed by the transformation of time–frequency components of responses for generating damage-sensitive relationships, Bayesian models describing the crack-sensitive relationships hidden in the members of the damage index, and a mechanism synthesizing individual assessment results associated with the different reference models for providing one quantitative solution. The abnormal change in the stable relationships derived from the index can reflect damage occurrence and severity. The Bayesian approach is adopted to model the relationships under uncertainties of in-service railway turnout. The models trained by using monitoring data of the turnout rail before being damaged serve as a reference for healthy state, and deviations of actual observations from model predictions may indicate the existence of damage. The synthesizing process helps to offer a more rational assessment result through the weighted summation of individual quantitative assessment results. Rail monitoring data of a railway turnout are acquired to examine the damage detection performance of the proposed method. By exempting loadings measurement and physical model derivation, this data-driven methodology is potentially capable of supporting the damage identification and quantitative assessment of other structures in railway engineering.

Research on Cost Control of Railway Engineering Based on Grounded Theory

An analysis of cost management within railway construction projects has been conducted using the Analytic Hierarchy Process (AHP) and a regression analysis to evaluate and rank key financial and operational factors affecting project costs. This research assesses the impact of various metrics, such as Safety Inspections, Emergency Preparedness, and Equipment Maintenance, along with financial indicators such as Actual Cost and Variance, on cost control strategies by building a hierarchical model and implementing AHP. The results indicate a clear preference for Financial Metrics, with a priority vector of 0.667, over Operational Metrics, which have a priority vector of 0.334. Among the Financial Metrics, Actual Cost, with a priority vector of 0.565, is identified as the most influential, underscoring the importance of direct cost management. Among the Operational Metrics, Emergency Preparedness is the most important, with a priority vector of 0.540, emphasizing the importance of effective risk management. A regression analysis confirms these priorities, with significant correlations presented between these metrics and variances in costs. According to this study, changes in Emergency Preparedness and Equipment Maintenance can predict cost fluctuations, aligning with the findings of the AHP study. The AHP evaluations are demonstrated to be reliable, with consistency ratios significantly below the 0.1 benchmark (0.043 for Financial Metrics and 0.008 for Operational Metrics), indicating a high degree of consistency in judgment. The statistical validation enhances the framework’s effectiveness in steering strategic decisions regarding cost management. This paper discusses the implications of these results to reduce financial risks and improve project outcomes.

Numerical investigation on the deformation of railway embankment under normal faulting

Active faults in the earthquake region are consistently regarded as a potential geological hazard to the construction and operation of railway engineering. However, the effects of normal faulting on railway embankments have not been investigated thoroughly. For bridging this knowledge gap, three-dimensional finite element analysis considering the influence of faulting offset, the soil layer’s thickness, the fault dip angle and the embankment cross-fault angle are conducted to clarify the normal faulting effects on the railway embankment. Emphasis is given to the stress and strain characteristic in the fault rupture outcropping regions on the embankment, the deformation of the embankment centerline for design purposes, and the determination of the affected zones for railway embankment preservation. The analysis shows that the normal fault rupture outcropping regions on railway embankment are tensile yield in most cases. The existence of the soil layer and its thickening would widen the affected zones and the regions where the fault ruptures outcrops. The fault dip angle and the cross-fault angle of the embankment have a complex effect on the behaviors of the crossing embankment. The depth of the subsidence zone of the embankment would increase with the decrease of the fault dip angle and the large fault dip angle would change the primary fault rupture to be a compressive one directly above the fault line. If the embankment crosses the fault line obliquely, the curvature radius of the centerline would hardly meet the design code.

Advancement of data-driven SHM: A research paradigm on AE-based switch rail condition monitoring

The past ten years have witnessed the tremendous progress of structural health monitoring applications in civil infrastructures. This is particularly embodied in railway engineering. The increasing train speed brings greater challenges to safety and ride comfort, and the primary theme of maintenance has been gradually altered from offline inspection to online monitoring. Rail operators must get an in-time warning of potential structural defects before critical failure takes place. It is more favourable that the rail operators can take hold of the real-time status of the key components and infrastructures in railway systems. This paper summarizes a long-term research series by the authors’ research team on online monitoring of rail tracks at turnout areas utilizing acoustic emission-based sensing technique, and more importantly, successively advancing signal processing methods and data-driven analysing frameworks, covering Bayesian inference, convolutional neural networks, transfer learning and task similarity analysis. The proposed algorithms tackle noise interference brought by wheel-rail impacts, great uncertainties in an open environment, and insufficiency of monitoring data, and realize comprehensive monitoring of rail tracks in turnout areas from basic crack detection to regressive condition assessment step-by-step.

Do Algorithms Dream of Electric Requirements? Leveraging AI‐Based Approaches for Automated Allocation and Classification of Requirements in Railway Engineering

AbstractIn recent years, Artificial Intelligence has experienced an extraordinary growth. Systems Engineering is a discipline where the implementation of AI can be challenging, but that could immensely benefit from its capabilities. This paper presents one of the many implementations that AI can have within the Systems Engineering field. AI has been leveraged to create an algorithm that allows for the automatic identification and classification of requirements within a specific engineering sector: large railway projects. While text classification algorithms are well established, the key to a successful implementation of a requirements classification algorithm lays on the effective structurization of the data, as well as the high quality of the training datasets. This paper describes how an AI‐based requirements classification algorithm has been planned and trained to effectively classify requirements in future documents based on systems and subsystems from a System Breakdown Structure (SBS), as well as to predict the adequate method of verification for both the Design and Testing and Commissioning stages of a railway project.Finally, the paper showcases how the use of this AI‐based requirements classifier does not only lower the probability of human error, but also reduces ∼75% human workload per project. Additionally, overall ∼30% cost savings to organizations are expected in a 10‐year period in the task of classifying requirements with respect to manual classification performed by subject matter experts.

Influencing Factors Analysis in Railway Engineering Technological Innovation under Complex and Difficult Areas: A System Dynamics Approach

The geological complexity, environmental sensitivity, and ecological fragility inherent in complex and difficult areas (CDAs) present new opportunities and challenges for technological innovation in railway engineering development in China. At the current stage in China, the process of technological innovation in railway engineering within CDAs still faces a series of pressing issues that need addressing. The paper identifies and determines 22 influencing factors for technological innovation in railway engineering within CDAs across five dimensions. Subsequently, a technological innovation model for railway engineering in such areas is constructed based on system dynamics (SD), which is followed by simulation and sensitivity analysis to identify the key influencing factors. The results indicate that key influencing factors for technological innovation in railway engineering within CDAs include technological innovation capability, the adaptability of technology to the environment, R&D funding investment, technological product requirements, technological innovation incentive mechanisms, and the level of technological development. The importance ranking of each dimension is as follows: technological factors > technical factors > management factors > resource factors > environmental factors. The paper provides new insights for promoting technological innovation and management development in complex and challenging railway engineering projects. It offers a fresh perspective to enhance the technological innovation efficiency of railway projects in complex and challenging areas.