PurposeThe purpose of this study is to reduce wheel–rail vibration noise (with the noise level increasing by approximately 9 dB for every doubling of train speed) by enhancing wheel damping. Besides, it verifies the performance of the damping wheel and provides support for the engineering application of low-noise wheels.Design/methodology/approachThis study takes the damping ring-constraint layer composite wheel as the research object. First, it proposes a wheel scheme combining a damping ring and constrained damping. Then, it verifies the natural frequency and damping of the proposed wheel via 3D finite element modeling and modal analysis. Finally, in the laboratory, the wheel–rail relationship test setup is used to conduct tests on two types of wheel structures (nondamping wheel and damping wheel) under radial and axial excitation.FindingsThe damping wheel significantly reduces the corresponding radiated sound power level, with an overall noise reduction of approximately 10 dB or more, especially in the high-frequency region (around 3,150 Hz). The damping ring reduces high-frequency noise, while the constraint layer suppresses medium-low frequency noise. The combined structure outperforms single-component structures in the full frequency range, as it can suppress both high-frequency whistling noise and medium-low rolling noise.Originality/valueThe originality of this study lies in proposing a wheel scheme that combines a damping ring and constrained damping. The study’s value is to provide a theoretical basis and technical guidance for the engineering application of low-noise wheels in rail vehicles.
Transportation engineering, Railroad engineering and operation
Purpose – This study is dedicated to systematically collating the distribution and utilization circumstances of geothermal resources in China. Moreover, it endeavors to formulate a comprehensive utilization scheme for geothermal resources during the construction and operation phases of the railway, thereby furnishing robust support and valuable reference for the holistic utilization of geothermal resources along the railway corridor. Design/methodology/approach – Through an in-depth analysis of the extant utilization of geothermal resources in China, it is discerned that the current utilization modalities are relatively rudimentary, bereft of rational planning and characterized by a low utilization rate. Concurrently, by integrating the practical requisites of railway construction and operation and conducting theoretical dissections, a comprehensive utilization plan for the construction and operation periods of railway is proffered. Findings – In light of the railway’s construction and operation characteristics, geothermal utilization models are categorized. During construction, comprehensive modalities include tunnel illumination power generation, construction area heating, tunnel antifreeze using shallow geothermal energy, tunnel pavement antifreeze and construction concrete maintenance. During operation, they comprise operation tunnel antifreeze, railway roadbed antifreeze, railway switch snow melting and deicing, geothermal power station establishment and railway hot spring health tourism planning. Originality/value – According to the characteristics and actual needs of railway construction and operation, it is of great significance to rationally utilize geothermal resources to promote the construction and operation of green railways.
Transportation engineering, Railroad engineering and operation
Abstract: Weather conditions always have a huge impact on air transport. Taking into
account global climate changes, which have a great influence on such conditions, this
problematic continues to be one of the most current research topics, especially in the context
of the above-mentioned field of transport. This article attempts to present the issue of the
Urban Heat Island (UHI) and its potential influence on air transport. The aspects of lightning
discharges and torrential rains, which are often accompanying them, were also discussed.
Additionally, infrastructural and procedural solutions reducing the negative effects of
unfavourable weather conditions are described.
Keywords: Urban Heat Island; Air transport; Weather conditions
Highway engineering. Roads and pavements, Bridge engineering
Introduction. An urgent task today is to optimise the interaction between rolling stock and the railway track. A solution to it will increase train speed, enhance the safety and service life of wheels and rails. The service life of wheels and rails is under significant influence of contact stress and pressures. Their magnitude depends on the track geometry, including rail canting, contact spot and elastic properties of the contacting elements.Materials and methods. The authors analysed the effects of rail canting on contact stress and pressure in the wheel – rail system at various loads from the rolling stock wheels, and assessed the effects of the underrail base elasticity on deformation and stress in the contact spot ignoring the force interaction between the track and the rolling stock when the overall stiffness of the track changes. Thus, this work sets the magnitude of the forces transmitted from the wheels of the rolling stock to the rails as the input data for determining the stress-strain state of the wheel – rail system. For the analysis, the authors developed a finite element model for calculating the stress-strain state of the wheel – rail system at various compaction degrees of the underrail base. The analysis of the obtained calculated data led to conclusions about the influence of the underrail base elasticity and the canting on the contact stresses and pressures in the wheel – rail system. The authors also assessed the effects of rail canting on the stress-strain state of the wheel – rail system for deviations from the standard position within the allowed limits.Results. The calculation results show that the change in the underrail base elasticity has a weak effect on contact pressures and stresses (excluding the effect on the immediate force interaction of the rolling stock and the track). At the same time changes in the canting within the allowable values from 1/12 to 1/60 causes the contact stresses to exceed the yield strength of the rail steel, which, among other reasons, reduces the durability of the material and, as a result, reduces the service life of the rails, and, at the same time, increases the risk of brittle fracture in the area of extreme mechanical stress.Discussion and conclusion. The obtained results of the calculation show that such a parameter of the rail track as canting requires control, since a change in the stress-strain state of the rails due to a change in canting affects their service life and traffic safety in general. It is suggested to automated and manual diagnostic tools to monitor this parameter.
Železničná osobná doprava je optimálnym prepravným systémom pre obsluhu významných sústredených prepravných prúdov. Napriek množstvám výhod tohto systému, jeho dlhodobý úpadok znamenal postupnú rezignáciu na úlohu železnice ako nosného dopravného systému a jej transformáciu na podporný systém počas prepravných špičiek pre čoraz nosnejšiu autobusovú dopravu. Cieľom predkladaného príspevku je na základe objektívnych kritérií identifikovať zmysluplné (perspektívne) linky železničnej osobnej dopravy a určiť, koľko vlakov vo verejnom záujme, odkiaľ, kam a kedy má na nich premávať a aké majú byť vzájomné prestupy v uzloch. Tento plán bude vychádzať z plánu dopravnej obslužnosti a bude spracovaný na celoštátnej úrovni a mal by slúžiť ako pilotný základ objednávky výkonov vo verejnom záujme v železničnej doprave v SR. Východiskom optimálneho stavu (do roku 2030) je následná konsolidácia železničnej osobnej dopravy na všetkých perspektívnych tratiach do podoby, zodpovedajúcej príkladom dobrej praxe na úrovni európskeho štandardu. Nevyhnutným predpokladom pre realizáciu tohto optimálneho stavu je investičný rozvoj týchto železničných tratí. Príspevok je súčasťou riešenia projektu VEGA č. 1/0837/21 “Priestorové a časové aspekty politiky súdržnosti EÚ: skúsenosti a perspektívy”.
Railroad engineering and operation, Industrial engineering. Management engineering
The sealing performance of the vehicle is the key factor affecting the comfort experience of passengers, and the sealing performance of the door system directly determines the sealing performance of the vehicle. Therefore, it is of great significance to improve the sealing performance of the door. The factors affecting the sealing performance of the vehicle were analyzed, such as the blocking ratio and the running speed of the vehicle, and the improvement of the sealing performance of the sliding plug door system was studied combined with the comfort evaluation standard. The method to optimize the sealing performance of the door system by adding restraint limit and improving the rubber strip section was proposed, which was verified by bench pressure charging test. The results show that the sealing performance of the door system can be significantly improved by adding constraints and pneumatic pressure locking at the lower part of the door leaf, and the asymmetric finger protection rubber strip with reverse lip edge also has a certain effect on improving the tightness of the door system, which provides guidance and suggestions for the sealing structure design of door system of serialized China standard metro train.
HIGHLIGHTS Charcoal value chains in two Kenyan counties were anayzed to identify sustainability improvement opportunities. Charcoal value chain actors need specific inputs, skills and face different operational challenges. The trade is conducted in the informal sector, which increases the actors' vulnerability. Improvement needs include sustainable forest management, improved operations, business skills, and coherent policies. SUMMARY Developing profitable and sustainable charcoal supply chains in Sub-Saharan Africa requires good knowledge about their properties, input needs and impacts. Charcoal supply chains in Taita Taveta and Kwale counties, Kenya, were analysed to identify operational and sustainability improvement opportunities. Using operations management, lean engineering and participatory research, charcoal value streams' processes, resources, and outcomes were analysed. Charcoal production and trade have low entry barriers, slow-paced innovation, and thin profit margins for value chain actors. Production is labour intensive, and the actors need specific skills, knowhow, and resources for proper business performance. The value chain's profitability and sustainability can be improved by regenerating exploited quality tree species, improving operation efficiency and safety, promoting market development, and appropriate policies on charcoal production and trade. The study's findings can guide the development of enabling policies and regulatory frameworks for the charcoal industry and improve the actors' performance in the charcoal value chain.
The article describes features of operation and monitoring of low-water bridges, which are found on highways of regional, intermunicipal and local importance. Vibrations of the bridge span are considered in detail, taking into account its interaction with other structural elements and the environment. As a characteristic, the change of which takes into account the change in the state of the bridge structure, it is proposed to use the frequency of natural vibrations. To simulate the dynamic effects of transport and the dynamic behavior of individual elements and the entire structure as a whole, it is proposed to use viscoelastic elements of the Kelvin–Voigt type. When solving the problem, an approach has been implemented that makes it possible to take into account the anisotropic properties of the superstructure associated with various reinforcement along and across the roadway of the bridge, and to present the design scheme of the span not in the form of a beam supported at the edges with the help of hinges or viscoelastic dampers, but in the form of a plate, which can have different fxing conditions along the entire contour. The use of the proposed model and approach will make it possible to obtain the necessary data on the state of low-water bridges, for which there is often no possibility of visual inspection or instrumental inspection from the lower side of the bearing part of the superstructure. By the values of the frequency of natural vibrations, it is possible to estimate the water level above the low-water period and predict food situations, during which the roadway of the low-water bridge may be fooded.
Adoption by Russia of the Kigali Amendment to the Montreal Protocol on substances that deplete the ozone layer posed a very difficult task for consumers of artificial cold, including rail transport, to find an acceptable alternative to the R134a freon and mixtures based on it, which is being phased out. Considering that there are no equivalent alternatives to these substances on the market, it was proposed to consider the use of widely known and previously used working fluids in climate technology, based on the positive experience of the European Union (EU) countries. The article analyzes the reasons for the bans on the use of hydrofluorocarbons, presents the mechanism for the legal use of refrigerants that are safe for humans and nature in the EU and a version of the roadmap for converting the climatic units of the Russian Railways holding to R22 freon and other types of fluorocarbons within the framework of the Kigali Amendment.
The development of technologies associated with the fourth industrial revolution is rapid. Construction 4.0 represents the architecture, engineering, construction and operations industries exploration of new technologies, equivalent to Industry 4.0 for the manufacturing industry. These concepts address multiple perspectives besides the technological, such as management and processes. The purpose of this study was to investigate to what extent research regarding construction projects addresses information and communication, automatisation or industrialisation technologies. A scoping review was the method used to perform a quantitative analysis of over two thousand journal papers published from 2015 onwards. The results show that new technologies are addressed separately, while synergy studies are uncommon. Longitudinal analyses show that there was no significant increase in journal papers concerning new technologies from 2015 to 2019. Information and communication was the search criterion with the least number of papers found. The environmental perspective of new technologies was present but the least common from 2019 to 2020. Hence, this review shows that there is an extensive research gap regarding Construction 4.0 technologies in the context of construction projects. Studies regarding synergy and environmental effects of new technologies should increase to start the progress towards a successful entry into the fourth industrial revolution.
AbstractOne of the most critical components of the US transportation system is railroads, accommodating transportation for 48% of the nation’s total modal tonnage. Despite such vital importance, more than half of the railroad bridges, an essential component of railroad infrastructure in maintaining the flow of the network, were built before 1920; as a result, bridges comprise one of the most fragile components of the railroad system. Current structural inspection practice does not ensure sufficient information for both short- and long-term condition assessment while keeping the operation cost low enough for mandatory annual inspection. In this paper, we document the development process of an autonomous, affordable system for monitoring railroad bridges using the wireless smart sensor (WSS) so that a complete end-to-end monitoring solution can provide relevant information directly from the bridges to the end-users. The system’s main contribution is to capture the train-crossing event efficiently and eliminate the need for a human-in-the-loop for remote data retrieval and post-processing. In the proposed system, an adaptive strategy combining an event-based and schedule-based framework is implemented. The wireless system addresses the challenges of remote data retrieval by integrating 4G-LTE functionality into the sensor network and completes the data pipeline with a cloud-based data management and visualization solution. This system is realized on hardware, software, and framework levels. To demonstrate the efficacy of this system, a full-scale monitoring campaign is reported. By overcoming the challenges of monitoring railroad bridges wirelessly and autonomously, this system is expected to be an essential tool for bridge engineers and decision-makers.
Abstract Lifelines and infrastructure systems are among the most critical operational components of an urban environment to ensure a minimum level of post-earthquake economic and societal functionality following major seismic events. The overall performance of lifeline systems after the September 19, 2017 Mw 7.1 Central Mexico earthquake was generally positive. The most extensive impact was observed on the fresh water supply network within Mexico City (CDMX), which resulted in the temporary loss of water supply for nearly six million people, yet expedited repair work and temporary solutions limited severe interruption of daily operations and helped mitigate human suffering. The road, railroad and bridge networks were reported to have experienced very limited damage. Less than a dozen bridges indicated some level of damage in the areas affected by the earthquake. Only few selected rail stations within the public transportation system of Mexico City (metro) were temporarily closed for up to one month due to structural damage. The electricity network was reestablished to its full capacity within four days. Several case studies in the regions ranging from Mexico City to the earthquake epicenter (Puebla) are presented in this paper to provide an overview of engineering success stories as well as opportunities alike.
Daop 2 Bandung is one of the Indonesian railroad operations areas, under the administration of PT Kereta Api Indonesia (Persero). Daop 2 Bandung is currently experiencing a problem in predicting the number of passenger volumes. It is common for railway transportation services to experience passengers flows that increases or decreases in the volume which in turn causes the service of the PT. KAI becomes less optimum. Therefore, a forecasting information system is needed to forecast the volume of train passengers in the upcoming period. This study applied Double Exponential Smoothing method as a forecasting method. The data used is the number of passenger volume data for two periods, i.e. 2017 and 2018 periods. For forecasting accuracy, PE (Percentage Error) and MAPE (Mean Absolute Percentage Error) were used. The passenger volume forecasting results on the Executive Class category shows 946,824 with an error percentage of 11.9962%, the Business Class category shows 221,188 results with an error percentage of 21.6714%, and the Economy Class category shows 5,144,074 with an error percentage of 10.4366%.
Hybrid SiC IGBT uses SiC Schottky diode to replace the anti-parallel diode in traditional IGBT devices, which can reduce the diode reverse recovery loss and IGBT turn-on loss. Compared with the traditional Si IGBT device, the performance of hybrid SiC IGBT is greatly improved, and compared with high-voltage and high-power all SiC devices, hybrid SiC IGBT has greater advantages in cost and technology maturity. According to the characteristics of hybrid SiC IGBT devices, a converter module with low stray inductance in converter circuit was developed to meet the application requirements of hybrid SiC IGBT devices, and the influence of stray inductance of converter circuit on switching characteristics of hybrid SiC IGBT was studied. The experimental results showed that the stray inductance of converter module had a great influence on the amplitude and duration of switching on oscillation voltage of hybrid SiC IGBT, and the system loss could be reduced by about 25% by using hybrid SiC IGBT devices.
The development of airport infrastructure and creation of airline hubs, which have a great importance for the economy, encourage to thorough analysis of their role for airlines. Hub airports are the fundamental source of the competitive advantage of full service network carriers. This article explains their role for airlines. The paper presents also the most important properties of airline hubs, which affect the competitiveness of air carriers. It also presents major challenges related to the functioning of hub airports, which have to be addressed by airlines. These issues are very current due to planning of the new central transport hub in Poland. Keywords: Hub airport; Airlines; Competitiveness; Network carriers
Highway engineering. Roads and pavements, Bridge engineering
V. A. Baboshin, Transport n.a. Army General A.V. Khruljov, Konstantin N. Savinov
et al.
The Railway Troops of the Armed Forces of the Russian Federation are intended for technical cover, restoration, demining and barrage of sections (objects) of the RF railroad transport infrastructure in the RF Armed Forces responsibility zone, increasing its survivability and carrying capacity, as well as planning the guidance and operation of floating railway bridges. The railway infrastructure is understood as "a technological complex, which includes subsystems of railway infrastructure, components of subsystems and elements of components of subsystems of railway infrastructure, ensuring the functioning of this complex" [1]. The tasks of the troops include the operation of existing and construction of new sections of railways, bypassing railway (railway) junctions, the construction of temporary railway bridges in order to ensure the actions of troops [2]. When restoring infrastructure facilities for railroad transport, the organization of work management and the promptness of restoring interrupted train traffic play a decisive role, which largely depends on the preparation and decision-making that requires certain engineering calculations. In particular, the development of design documentation for the construction of a bypass of a destroyed section of a road or a railway junction requires a significant amount of time. The most time-consuming document of design documentation is the calculation and construction of a longitudinal bypass profile. The article discusses the issues of automated construction of a longitudinal bypass profile, which can significantly reduce the time required for preparing design documentation, including for laying cable lines to restore the regulation of train traffic.
Steam generators for NPPs are the important large-sized metal consuming equipment of nuclear power installations. Efficiency of steam generator operation determines the overall service life of the whole nuclear facility. The main aim of the current study is to analyze advantages and shortcomings of horizontal and vertical types of steam generator design. This analysis is aimed at the development of recommendations for designing advanced steam generators for future Russian units of NPPs with VVER reactors of increased power. Design solutions and fifty-year experience of operation of 400 steam generators of horizontal type accepted in Russia and of vertical type applied by Westinghouse, Combustion Engineering, Siemens, Mitsubishi, Doosan were analyzed within the framework of the present study. Advantages and drawbacks of both types of equipment determining the development of conditions of the operating processes were also identified and systematized. Currently NPPs equipped with VVER are characterized with extended surface area of containment shells due to the application of four-loop design configuration and horizontal-type steam generators. It was established that steam generator equipment of horizontal type is characterized by such inherent disadvantages of design, technological and operational nature as the following: 1) small height and volume of the vapor space above the evaporation surface reducing separation capabilities and the capacity of the equipment as a whole; 2) impossibility of organizing separate single-phase pre-boiling section. Because of the above, horizontal steam generators with dimensions permissible for railroad transportation and, for VVER-1200 with reactor vessel diameter equal to 5 m, by water transport as well, have exhausted the possibilities for further significant increase of the per unit electric power. The demonstrated advantages of vertical-type steam generators were as follows: 1) absence of stagnant zones within the second cooling circuit, and, consequently, of hold-ups in them; 2) uniformity of heat absorption efficiency of the heating surface ensuring, as well, improved conditions for moisture separation; 3) high degree of moisture removal from steam-water mixture due to the combination of moisture separating elements of chevron and swirl-vane types; 4) increased temperature drop with parameters of generated steam elevated by 0.3 – 0.4 MPa. Conclusion was made on the advisability of introduction of steam generators with vertical-type layout in the Russian nuclear power generation. Practical tasks that need to be addressed in order to ensure introduction of vertical steam generators at NPPs with high-power VVER reactors were formulated.