Railway Engineering Research Articles

Distribution characteristics of coal mining subsidence areas in Sichuan Province and their influence on traffic engineering construction

Traffic engineering construction in coal mining subsidence areas must consider long-term safety. Thus, this paper comprehensively analyzes the status and characteristics of Sichuan’s coal mining subsidence areas, expounds their influence on railway and highway engineering construction, and investigates comprehensive countermeasures combining national policies and related technical requirements. The findings of this study can serve as a reference for the design, construction, operation, and maintenance of traffic engineering construction in coal mining subsidence areas.

Identification of vertical wheel-rail contact force based on an analytical model and measurement and its application in predicting ground-borne vibration

Wheel-rail interaction plays an important role in the study of railway engineering. The wheel-rail contact forces (WCFs) are the key factors in the models addressing wheel-rail interaction. However, it is sometimes difficult to be measured, so an indirect identification methodology is proposed in this paper. Based on an analytical model and measurement, the vertical WCF can be determined. Using measured rail accelerations as input data, a calculation program is developed. The vertical WCF and the excitation forces transmitted from the vehicle-rail system to the roadbed can be obtained. The latter forces are used to predict the train-induced ground-borne vibrations. A case study of predicting ground-borne vibration in Beijing Metro is presented to verify the effectiveness of this method. The results show that the vertical WCF can be obtained efficiently and accurately, and the predicted ground-borne vibrations have good agreement with the measured ones.

A comparative review on American, European and Chinese standard for railway concrete sleeper

This article discusses the similarities and differences of American, European and Chinese standard for railway concrete sleeper. As an integral part of railway structure, concrete sleeper which is widely used in railway engineering plays an important role in the stability of the railway structure. To ensure the quality of concrete sleeper, different regions stipulate standard for concrete sleeper on the basis of technology development and geographical environment. A comparative review on concrete sleeper standard from America, China and Europe in terms of requirements on cement, aggregate, reinforcement, manufacturing and concrete properties has been conducted. The review shows that all of three regions have similar requirement on cement in terms of compressive strength and SO3 content. The aggregate requirement for both American and Chinese standard specifies the upper (D) and lower (d) limits of sieve size while the European standard which provides more flexible requirement specifying only the ratio D/d. Both of European standard EN 13230-1 and American standard AREMA CHAPTER 30 focus more on prestressing reinforcement including wire, strand and bar, while the Chinese standard GBT 37330 has more specific requirement for manufacturing process of concrete sleeper on the basis of steel reinforcement. The value of compressive strength of concrete stipulated by GBT 37330 is the highest. This paper could provide clear understanding of the production requirements of concrete sleeper in America, China and Europe which can be used as guide for further concrete sleeper development in the future.

Team durability test of a 1.3 MW locomotive diesel engine with prototype piston rings

Objective of this work was to realize a test of durability of railway engine EMD645 with power about 1300 kW. Within the framework of this test were investigated a prototyped piston’s rings with diamond embankment. Piston rings are made of chromium layer with including of diamond powders technology with a porous chromium coating, where in pores is deposited on said diamond powder with a grain size about 1 micron. The work will be carried out of an analysis of collaboration piston – piston rings – cylinder unit in internal combustion engine and an analysis of the use of hard materials (diamond powder) in friction pairs. During work of this unit we can observe wear of piston rings, precisely - of coating which is deposited on ring to prolong service life. After testing of the locomotive engine EMD645 on the basis of the collected results are developed conclusions of the wearing intensity on piston ring and relating them to the requirements for coatings. The work aims to show the possibilities and benefits of the application of new protective coatings on structural elements of the internal combustion engine in order to reduce their wearing, which is consistent with the observed trend of technology development.

High-Resolution Modeling and Apportionment of Diesel-Related Contributions to Black Carbon Concentrations.

Exposure to diesel-related air pollution, which includes black carbon (BC) as a major component of the particulate matter emitted in engine exhaust, is a known human health hazard. The resulting health burden falls heavily on vulnerable communities located close to major sources including highways, rail yards, and ports. Determination of source contributions to the overall pollution burden is challenging due to collinearity in the exhaust composition profiles for relevant sources including heavy-duty diesel trucks, railroad locomotives, cargo-handling equipment, and marine engines. Additionally, the impact of each source depends not just on the magnitude of emissions but on its location relative to receptors as well as on meteorology. We modeled source-resolved BC concentrations in West Oakland, California, at a high (150 m) spatial resolution using the Weather Research and Forecasting model. The ability of the model to predict hourly and 24 h average BC concentrations is evaluated for a 100-day period in summer 2017 when BC was measured at 100 sites within the community. We find that a community monitoring site is representative of population-weighted average BC exposure in the community. Major contributing sources to BC in West Oakland include on-road diesel trucks (44 ± 5%) and three off-road diesel sources: ocean-going vessels (19 ± 1%), railroad locomotives (16 ± 2%), and harbor craft such as tugboats and ferries (11 ± 1%).

Improving Wheelset Stability of Railway Vehicles by Using an H∞/LPV Active Wheelset System

The complexity of railway vehicle structures has been part of an evolutionary process for almost two hundred years. Challenges such as increased weight, increased maintenance, higher costs and energy consumption have become common. The vision for future railway vehicles is to reduce complexity, hence enable simpler structures and reduce maintenance and cost, and of course various research challenges arise from this. In fact, a number of papers in the railway engineering literature have presented practical ways to control steering of railway vehicles to improve performance. The model of the railway wheelset is highly nonlinear, mainly due to the nature of the wheelset structure and the related wheel-rail contact forces involved during operation. In this paper, the simplest design in terms of retrofitting, the actuated solid-axle wheelset is considered, we investigate actively controlled wheelsets from a Linear Parameter Varying (LPV) control aspect. We use the grid-based LPV approach to synthesize the H∞ / LPV controller, which is self-scheduled by the forward velocity, as well as the longitudinal and lateral creep coefficients. The aim of the controller is to reduce the lateral displacement and yaw angle of the wheelset. Simulation results show that the proposed controller ensures the achievement of the above targets in the considered frequency domain up to 100 rad/s.

Risk and Safety Management of Railway Engineering Construction

Risk and Safety Management of Railway Engineering Construction

Study on the mechanical properties of outwash deposits with random structure method

Abstract Outwash deposit is one of the major threats to the safety and stability of railway transit engineering in the Sichuan–Tibet area. In this paper, different samples of outwash deposits were prepared based on the random structure method, and a series of large-scale direct shear tests were carried out under different normal stresses. The influence of stone content and the spatial distribution of stone blocks on the physical and mechanical properties of outwash deposits were studied. The results show that with the increase of stone content, the shear stress-displacement curve changs from strain softening to strain hardening. The shear zone is larger, and its shape is more tortuous due to the movement and rotation of stone blocks. The internal frictional angle increases linearly while the cohesion diseases with the increase of stone content. The main influence of the spatial distribution of stone blocks on the mechanical properties of outwash deposits is the peak stress. The shear zone is mainly determined by the distribution of the stone blocks near the shear zone.

Trends in the professional training of railway electrical engineers of railway transport

The article deals with the main trends in the professional training of railway electrical engineers, which determine the relations between railway universities and production. The trend of integration due to the unification of the content of education and the determinism of academic disciplines ensures the professional mobility of a specialist both within the profession and in related areas of production. Teaching at a sufficiently high level of difficulty, stimulating the active cognitive and creative activity of students, requires an intensification trend due to the compaction and increasing volumes of information flows, the rapid development of the technical and technological foundations of production. The trend of cooperation determines the main directions and forms of interaction of vocational training with production and other institutions of higher vocational education. The gradual development of the main functions of professional activity (production and technological, operational and managerial, administrative and regulatory), in the process of personnel development of railway electrification engineers, contributing to the progressive development of specialist competencies, increases the adaptation period to the conditions of professional activity, characterized by the complex impact of professional risks. The study of the experience of professional training of railway transport specialists revealed the need for the formation of professional and personal characteristics of railway electrical engineers, which ensure the reduction of the impact of professional risks set by the factors of danger, uncertainty and alternativeness.

Novel features for the detection of bearing faults in railway vehicles

In this paper, we address the challenging problem of detecting bearing faults from vibration signals. For this, several time- and frequency domain features have been proposed. However, these proposed features are usually evaluated on data originating from relatively simple scenarios and a significant performance loss can be observed if more realistic scenarios are considered. To overcome this, we introduce Mel Frequency Cepstral Coefficients (MFCCs) and features extracted from the Amplitude Modulation Spetrogram (AMS) as features for the detection of bearing faults. Both AMS and MFCCs were originally introduced in the context of audio signal processing but it is demonstrated that a significantly improved classification performance can be obtained using the proposed features. Furthermore, the data imbalance problem that is prevailing in the context of bearing fault detection, meaning that typically much more data from healthy bearings than from damaged bearings is available. Therefore, we propose to train a One-class SVM with data from healthy bearings only. Bearing faults are then classified by the detection of outliers. Our approach is evaluated with data measured in a highly challenging scenario comprising a state-of-the-art commuter railway engine which is supplied by an industrial power converter and attached to a gear and load.

Real-time hybrid testing for efficiency assessment of magnetorheological dampers to mitigate train-induced vibrations in bridges

ABSTRACT The dynamic response of railway bridges is important to consider, as the high velocity loading from the trains increases the risk of resonance. Increasing train speeds and loads result in a need for adaptable properties for railway bridges. One solution is to install magnetorheological dampers, as the response of the structure originating from moving loads could be controlled by alternating the input current to the damper. However, the complexity of such devices results in difficulties to accurately model their behaviour. From this context, real-time hybrid simulations, consisting of a numerical bridge model and a full-scale physical magnetorheological damper in a test frame, are presented in this paper. The novelty of the present paper is the application of RTHS in railway bridge engineering and the substructure combination with magnetorheological dampers. The results from the real-time hybrid simulations show that the bridge deck responses can be reduced to permissible levels.

Suggested Qualification Test Procedure to Secure Splitting Resistance in Pretensioned Concrete Members

Prestressed concrete ties could develop end-splitting cracks along tendons due to lateral bursting stresses. The lateral bursting stresses can form due to Hoyer effect (change in diameter of the prestressing tendons due to Poisson’s ratio), the jacking force in the tendons, geometrical features and indent characteristics of the prestressing tendons. End-splitting cracks can occur immediately after de-tensioning procedure in some cases, but they also can be developed during the first weeks after de-tensioning procedure due to sustained lateral stresses exerted by the prestressing tendons. The ability of concrete to resist these bursting stresses without cracking is primarily the function of the thickness of concrete cover, the type of concrete mixture used and the maximum compressive strength of the concrete. Qualification test will be great tool for prestressed concrete tie manufacturers to identify tie designs that may be susceptible to end-splitting cracks. This test was formally adopted as section 4.2.4 in Chapter 30 of the 2021 AREMA Manual for Railway Engineering.

Optimum Railway Transition Curves—Method of the Assessment and Results

This article discusses the optimization of railway transition curves, through the application of polynomials of 9th and 11th degrees. In this work, the authors use a 2-axle rail vehicle model combined with mathematically understood optimization methods. This model is used to simulate rail vehicle movement negotiating both a transition curve and circular arc. Passenger comfort is applied as the criterion to assess which transition is actually is the best one. The 4-axle vehicle was also used to verify the results obtained using the 2-axle vehicle. Our results show that the traditionally used in a railway engineering transition—3rd degree parabola—which is not always the optimum curve. This fact is especially valid for the longest curves, with lengths greater than 150 m. For such cases, the transition curves similar to standard curves of 9th and 11th degrees is the optimum ones. This result is confirmed by the use of the 4-axle vehicle.

FIRST RAILWAY ENGINEER

The Great Silk Road is one of the most significant achievements in the history of world civilization. An extensive system of caravan routes crossed Europe and Asia from the Mediterranean to China, and in Ancient times and in the middle Ages served as an important means of trade and communication between Western and Eastern cultures. The longest route passed through Kazakhstan and Central Asia. Since the appearance of the Great silk road, trade caravans passing through the modern land of the Kazakh people have had a great impact on the development of urban culture. One of the points of view is that these cities arose on the basis of caravanserais, while another point of view is based on the fact that they arose from the settlements of peoples who migrated from Central Asia during the existence of the Turkic States and established their own settlements. Historically, the road received the name “Silk Road” in connection with the silk trade, and later the word “Great” was added to this name because the road connected the vast Eastern and Western regions. Thus, this article attempts to answer the question of which mixed cultures arose as a result of the emergence of the largest urban cultures in the trading system, which went down in history as the “Great Silk Road”. Recently, historians have paid more attention to the modern history of Kazakhstan, while some issues of the medieval, in particular, the early medieval history of the Kazakh people have remained poorly studied. To fill this gap, the authors of the article focus on the analysis of the history of large cities of the early Middle Ages in Semirechye and Southern Kazakhstan, the main trade and economic centers and direct relations of Sogdian peoples with the Turks. The article provides a lot of information for students and doctoral students studying the medieval period.

Shakedown analysis and its application in pavement and railway engineering

This paper has been prepared in memory of Professor Scott Sloan. It first presents a brief review of the development of shakedown analysis methods for pavement and railway engineering problems. In particular, it describes a new lower-bound method using the concept of critical residual stress fields and an upper-bound method using a nonlinear programming technique, which were developed by the authors, and then extended and applied to solve various shakedown problems in pavement and railway engineering. Moreover, this paper summarises and compares shakedown solutions for pavement and railway engineering problems, whilst highlighting the key factors that influence the shakedown limits. In addition, this paper proposes a simple, unified shakedown limit equation for pavements and railways under repeated moving surface loads. The equation includes three terms, which represent the resistances from cohesion, self-weight of the underlying soil, and self-weight of any superficial rigid layers, respectively, in a format analogous to Terzaghi’s bearing capacity equation. Numerical results indicate that the coefficient in the cohesion term Ncsd depends on the soil friction angle; while the coefficient in the self-weight term Nγsd is controlled by the soil friction angle and a dimensional factor γa/c. Values of Ncsd and Nγsd for a typical rolling point contact problem are also presented and interpreted, which explain the different contribution ratios from the soil self-weight to the shakedown limits of pavement and railway problems.

An enhanced SHERPA (E-SHERPA) method for human reliability analysis in railway engineering

According to the European standard EN 50126 human reliability is a fundamental requirement in railway engineering. Notwithstanding that there are only few methods specifically developed for railway field. Trying to fill this gap, this paper proposes a human reliability analysis technique customized on railway applications to simulate a time-dependent model of the human error probability during the work shift. The first novelty of the proposed method is the use of customized task types for railway applications within a third-generation method. Furthermore, the concept of Eustress is considered to evaluate the impact of the stress on the operator performances by means of the Yerkes-Dodson law. The main novelty of the proposed method is the introduction of a simulator which provides the possibility of considering one or more breaks in the work shift allowing to simulate the error probability based on the duration of the break. The maintenance operations carried out on an Italian Automatic Train Protection System have been taken as case study to validate the proposed method in different scenarios. The results illustrate how a break during the working shift of the operator influences the probability of committing an error.

Hydrological ecosystem changes and impacts after the Zonag Lake outburst in Hoh Xil of Tibetan Plateau

After the iconic outburst of Zonag Lake in Hoh Xil of Tibetan Plateau (TP) in 2011, the causes of the collapse and its impact on the volume of water contained by the downstream lakes have highly been concerned, but the overall changes of the hydrological ecosystem and its impacts on the basin are yet not clear. This paper analyzes the hydrological system (lake area and hydrological connection) and ecosystem (sandstorm activity and vegetation growth status) changes and their impacts on the regional ecological environment after the outburst event, based on remotely sensed images from 2000 to 2020, meteorological observations, and field surveys. The results show that the outburst of Zonag Lake has not only changed the regional hydrology and ecosystem pattern but also caused a trend of degradation in the ecological environment of Zonag Lake Basin. Some lambing areas and active areas of Tibetan antelope in the area are being buried and eroded by the sandstorm. The downstream Yanhu Lake has risen to the highest level and overflowed through the emergency diversion engineering. These impacts are continuously threatening the health of the ecological environment of the world natural heritage site in Hoh Xil, the safety of Qinghai-Tibet highway, Qinghai-Tibet railway, and other engineering facilities, as well as the stability of fluvial geomorphology in the northern most sources of Yangtze River.

Velocity pulse effects of near-fault earthquakes on a high-speed railway vehicle-ballastless track-benchmark bridge system

The near fault (NF) line waves send out signal envelopes that oscillate over lengthy periods of time with periodic impulses. Like train bridges, train tracks demonstrate comparable track-bridge (TB) motion dynamics. Using these coupling dynamics, are the high-speed train-track-bridge (HSTTB) system designs sensitive to those parameters? This research incorporates a Finite Element Analysis (FEA) technique developed for simulating the dynamic reactions of the coupled TB system when faced with simultaneous NF lateral and vertical ground motions (GMs). For the first time, data from the pre-commissioning field testing of the Beijing-Shanghai high-speed train are utilized to validate the Train-Track-Bridge Dynamic Analysis (TTBDA) test. As a matter of fact, the current research has concentrated on the running safety of the high-speed train's operations, as well as the possible derailment mechanism of the high-speed train, in light of the far-field (FF) earthquakes. This analysis reveals that the NF GMs in the bridge structure's seismic reactivity are considerable. Many high-speed train derailments are due to frequent wheel displacement, elevated wheels, and significant lateral motion. The data discovered in the field may give engineers vital information for calculating relevant situations and railroad engineering projects.

Potential applications of solar refrigeration systems for permafrost cooling in embankment engineering

This paper presents the results of an evaluation of two solar-assisted refrigeration systems in protecting permafrost foundations in railway and roadway engineering. A technical comparison was conducted between two types of traditional permafrost cooling measures and refrigeration systems: vapor compression and heat-driven adsorption. The investigated refrigeration systems have better real-time performance and effectiveness than traditional passive heat regulation measures. Moreover, the permafrost regions in China have good potential for solar energy, addressing the issue of decentralized power supply for refrigeration. Two special permafrost cooling systems were designed, manufactured, and tested; the solar photovoltaic vapor compression refrigeration system (SPV-VCRS) and the solar photothermal adsorption refrigeration system (SPT-ARS). The SPV-VCRS prototype exhibits greater potential for permafrost protection, with a consecutive average temperature of −23.55 °C and a coefficient of performance (COP) of 0.41 in the warm season. The SPT-ARS prototype is characterized by an intermittent refrigeration temperature of −1.83 °C and a significantly lower COP of 0.054 per day. Based on the results, suggestions have been given for the selection of solar refrigeration systems for application in the protection of the permafrost under embankments.

Research on Experimental Teaching Reform of Railway Engineering under the Training of International Students

The railway engineering major shows extremely strong applicability, with the internationalization of railway engineering teaching and communication, how to solve the problem of cultivating the international students of the railway engineering major experimental teaching is a core problem that the railway engineering majors in universities need to solve at this stage. Through reform, a new type of experimental teaching system for railway engineering specialty was constructed, that is, the experimental course system and content system determined by the international students training program were taken as the core, the construction of teachers, experimental facilities, practice bases and other conditions as the basis, and the system construction and operation organization to build an organic whole composed of four elements for guarantee. It is closely integrated with the theoretical teaching system and relatively independent. It guarantees the realization of the goal of international students training. And it can integrate and optimize the experimental teaching links, content, methods and evaluation system, and build a “gradual experiment-professional experiment-comprehensive experiment” progressive gradient experiment teaching system. Form a benign pattern of collaborative training of laboratories, practice bases and scientific research bases, mutual promotion of teaching and scientific research, and effectively promote the improvement of students’ experimental innovation ability.