Hasil untuk "Railroad engineering and operation"

ZHANG Zhenhui, WEI Kai, PENG Shenyou et al.

To accurately identify and predict wheel-rail contact forces during the operation of heavy-duty trains, this paper proposes a novel method of decoupling and predicting these forces based on big data related to non-contact strain at the wheel periphery and a neural network. Initially, a refined finite element numerical simulation model was developed to replicate the wheelset-rail contact of heavy-duty trains. The subsequent analysis of strain sensitivity at the wheel periphery determined the optimal strain collection radius and the layout of collection points on the train wheels. The dynamic response of the wheel-rail contact area under various operating conditions of trains was investigated by analyzing extensive strain data generated at the strain collection points across multiple numerical simulation models, along with the vertical and lateral forces at the contact spots. The results revealed the variation patterns of response in key aspects such as strain and contact forces in the contact spot area when trains operating at a constant speed are accelerated. Following the establishment of a comprehensive data set of strain and contact forces, a neural network model correlating wheel-rail contact forces with non-contact strain at the wheel periphery was established, through a training process to address the relationship between contact forces and non-contact position strain. This model enables the real-time decoupling and accurate prediction of contact forces at the contact spot for trains. This neural network model exhibits superiority in both computational efficiency and prediction accuracy, proving effective in guiding the decoupling identification of wheel-rail contact forces for heavy-duty trains and supporting further engineering applications, such as solving the train derailment coefficient.

YANG Deyong, ZHU Bingquan

The traction system of urban rail transit vehicles is recognized as one of the main electromagnetic interference sources significantly impacting the electromagnetic compatibility of trains, primarily attributed to the implementation of pulse width modulation control, which involves high voltage, high current, and pulse interference characteristics. This study analyzed the main electromagnetic emission loops of the traction inverter system, taking into account both the vehicle system design and the flow path of electromagnetic interference current. By establishing a simplified calculation model for high-frequency interference currents, this study explored the method for designing filtering parameters aimed at reducing electromagnetic emissions from the traction system. Moreover, a comparative simulation was conducted to evaluate the suppression effects of various filtering schemes. Finally, the effectiveness of the proposed optimization method was verified by external radiation emission tests using trains.

FAN Qingyu, CHI Maoru, LUO Yun et al.

Based on the principle of hydraulic anti-kink system, a four-module single vehicle type tram model with traditional wheelsets and a simplified dynamic model of the anti-kink system was established for the bending phenomenon caused by the single-type tram passing through the curve. The force condition and the dynamic performance of tram passing through C-shaped circular curve and S-shaped curves with different intermediate straight line lengths were compared and analyzed under the action of anti-kink system. The results show that: 1) In terms of limits, the anti-kink system can make the head-shaking angle difference between the front and following car body and the bogie of the same module tend to be consistent on a small radius curve, effectively reducing the maximum head-shaking angle of the vehicle, and preventing the vehicle from bending on the curve. 2) In terms of dynamics, when passing the C-shaped circular curve and the S-shaped curve with a long intermediate straight line, the installation of the anti-kink system is conducive to the smooth entry of the rear vehicle into the curve, the wheel-rail lateral force and the derailment coefficient of the front guide wheel of the same module increase slightly, while the wheel-rail lateral force and the derailment coefficient of the following guide wheel guide decrease. When passing the S-shaped curve with a short intermediate straight line, the installation of the anti-kink system is not conducive to the curve passing, in the same module, the wheel-rail lateral force and the derailment coefficient of the front and the following guide wheel both increase. 3) It is not recommended to install hydraulic anti-kink system on the S-shaped curve when the length of the intermediate straight line is less than the fixed distance of the bogie; On the contrary, the tram may consider installing hydraulic anti-kink system.

S. Kapodistria, M. Katehakis, S. Ross et al.

B. Ploeckl, H. Köhnlein, T. Engelhardt et al.

Cryogenic pellet injection will be the prime candidate to fuel future fusion power plants. In order to harvest optimum fueling performance, it is essential to inject pellets from the magnetic high field side of the tokamak. The pellet launching system of the tokamak ASDEX Upgrade injects cryogenic hydrogen pellets with a speed of up to 1000 m/s from the magnetic high field side via curved guiding tubes. Pellets passing the guiding tube are sliding on a gas cushion, generated by the Leidenfrost effect. The actual track has a rectangular cross section and is composed of a series of ellipses in order to generate the required 270° looping type turn; the path length is 17 m. The last part of this track is marked by strong geometrical constraints from the vacuum vessel port. The previous design was composed of a sequence of three sections of ellipses too, tangentially constant but discontinuous with regard to the curvature. It had been in operation for almost 20 years. Its steps in the curvature are supposed to limit the system performance. A novel and advanced geometry concept, adopting a method well-known from civil engineering (e.g., for the railroad track design), has been applied to develop an improved design. It relies on clothoid shape sections keeping the track curvatures continuous and, thus, provides a smooth transition between all the elements. The new design presented improves the pellet launching system performance on ASDEX Upgrade and provides knowledge for an advanced design of pellet guiding tubes in future fusion devices.

A. Baldwin, Leo Lasecki, D. Mohrbacher et al.

Implementation of miscible gas huff and puff (HnP) for Improved Oil Recovery (IOR) requires timely identification of prospective projects, a demonstration of economic feasibility through pilot testing, and efficient scale-up of HnP operations. HnP pilot design and execution of the pilot project requires a minimum of 9 to 12 months to procure, and another 8 to 12 months to construct and operate. A substantial capital investment, approximately $1 to $5 million per pilot well, is also required (Texas Railroad Commission & Industry Operators). The lead time for procuring specialized compression can require 9 to 15 months. These early purchases comprise a large proportion of project capital investment. Collaboration by a variety of technical disciplines is required to efficiently design, construct, and operate a pilot with the goal of expanding IOR operations. An effective, collaborative approach allows for development of a HnP design that integrates both subsurface and surface design criteria. A workflow for design of HnP pilot testing was developed to coordinate concurrent project efforts including completion of reservoir characterization, engineering, permitting, stakeholder review and approvals, gas contracting, construction, testing and full-scale execution. Effective coordination of these efforts will result in efficient project implementation with minimal impacts on project scope, schedule and cost. Use of the workflow also allows for timely identification and mitigation of multiple project risks associated with design, construction and operation of IOR. Well executed pilot tests will accelerate the learning curve for application of HnP IOR in Eagle Ford wells; resulting in lower capital costs, lower operating costs, and increased operational reliability. Pilot test results will also be used to up-scale IOR operations in a cost-effective manner.

Shanqiang GU, Jingdi SUN, Rui ZHANG et al.

Aiming at the internal overvoltage phenomenon during high-speed train operation, the overvoltage formation mechanism and its influencing factors were analyzed by taking the case of the overvoltage in passing neutral section and the overvoltage of pantograph raising and dropping, and a simulation model for verification was built. In order to reduce the internal overvoltage of high-speed train, three measures of parallel blocking high-pass filter in neutral section, adopting advanced co-phase traction power supply system and selecting suitable roof voltage transformer were proposed. The results showed that the internal overvoltage of the high-speed train was related to the voltage phase of the catenary at the time of operation and the impedance of the voltage transformer, the three overvoltage suppression methods proposed could effectively reduce the overvoltage with simulation.

Wenchao QIU, Shusong YANG, Xiaodong JIANG et al.

For the purpose of improving the redundancy of the auxiliary power supply system of the metro vehicles, the grid connected power supply technology and the high-frequency converter technology were applied to line 4 and line 2 phase II project of the Ningbo metro. 4 SIV were grid connected to provide AC 380 V to the metro vehicles which grouping up with 4 motor cars and 2 trail cars. Meanwhile, 4 DC charger provided DC 110 V to the DC control circuit and the storage battery. The circuit composition, principle and characteristics of metro vehicle power supply system of Ningbo rail transit line 4 and line 2 phase II project were expounded. The application of grid connected power supply technology would improve the redundancy of auxiliary power supply system of metro vehicles.

Yu. N. Bulatov, A. Kryukov, N. V. Huan

Under current conditions, power consumers can create efficient distributed generation (DG) plants. DG plants can be connected to electrical power systems (EPS) via direct current (DC) links, based on power electronics elements. This allows ensuring high power quality and power supply reliability, and limiting the short circuit (SC) power in the DG sources buses. DG plants operating on the basis of synchronous generators allow developing a sufficiently large power. The efficiency of such plants in various modes depends on the settings of the automatic speed regulator (ASR) of rotor spinning systems and generator automatic voltage regulator (AVR). Currently, many tuning methods and algorithms for the operation of regulators of synchronous generators are offered. At the same time, the operation of ASR and AVR of DG plants under conditions of lower power quality and their impact on the electrical energy quality are not sufficiently studied. The article presents modelling results for transient states in microgrids designed for power supply of AC railroads non-traction consumers. The studies were conducted in the MATLAB system using the Simulink and SimPowerSystems software packages. The following events were considered as transitional modes: microgrid main power supply shutdown and activation of backup power supply; connecting an additional traction load that deteriorates the quality of electrical energy in the microgrid. The results of the DG plant and DC link influence on the electrical energy quality are presented, according to which it was established that the DG plants can be used to improve power quality.

V. Tsvetkov, K. Zoidov, A. A. Medkov

The presented study identifies modern trends in the innovative development of transport modes as the basis for the formation of a transition economy in the Eurasian space. Aim . The study aims to determine directions for the innovative development of transport modes based on the formation of a unified digital transport and logistics environment, and to find the most efficient ways of regulating financial flows from the transit passage of goods. Tasks . The authors develop and implement mechanisms for generating, distributing, and redistributing income from the functioning of a transit economy in the Eurasian territory in the context of automation, robotization, digital transformation, implementation of artificial intelligence, and transition towards paperless and unmanned technology. Methods . This study uses the methods of systems analysis, evolutionary-institutional theory, the theory of engineering and manufacturing balance, and historical approach. Results . The following directions for the automation and digital transformation of rail cargo transport in the Eurasian space are determined: reduction of the time spent on completing procedures at borders and stations; innovative development of the railroad infrastructure in the neighboring countries; automation of transportation, implementation of unmanned technologies; overcoming negative trends in the transportation of perishable items. Directions for the development and production of an innovative rolling stock for cargo transit are identified. Directions for the innovative development of road, sea, and air transport in the Eurasian space are analyzed, including the development of piggyback (raidroad) transport and uberization of the road cargo transport market. It is found that construction and commissioning of ice-class container ships is an innovative direction in the development of sea transport that transports cargo between Asia and Europe. The main direction in the development of air transport involves expanding consolidation and distribution cargo operations when flying over the Eurasian territory. Conclusions . Innovative transit transport systems (ITTS) are developing rapidly, which calls for the development and implementation of a mechanism for generating, distributing, and redistributing income from the transit of goods and passengers. This should be a corporate mechanism, i.e. it should be implemented via public-private partnership. The Eurasian Transit Transport Company could act as such a corporate structure in the Eurasian space. The most efficient way of distributing income from the functioning of a transit economy among the majority of economic agents is to develop the associated and related production of goods and services on a high-tech basis and to form a vast innovative industrial trade-route belt.

Yulong ZHU, Zhenpeng LI, Jie DING et al.

It was found that the noise of traction converter was prominent when a high-speed EMUs was running, resulting in a harsh whistle, which seriously affected the sound comfort. Aiming at this phenomenon, the acoustic tests of converter were carried out in the field and workshop. The acoustic characteristics were understood and the source of the whistle was determined. On this basis and concerning the converter structure and sound propagation characteristics, the optimization scheme of acoustic control was proposed and the acoustic simulation calculation and test verification were carried out for this scheme. The results showed that the optimization scheme could significantly improve the noise level of the converter and improve the comfort.

D. Campbell, Tsuyoshi Akiyama, R. Barnsley et al.

Zhendong Liu, S. Stichel, A. Rønnquist

Abstract Finding a simple and practical method to improve the dynamic behaviour of a specific structure is always desirable in civil and mechanical engineering. The railway catenary system is the overhead power line above the track, interacting together with the train-based pantograph to transfer electric power. Due to vertical stiffness variation and a propagating wave along the catenary, the fluctuation of the contact force becomes significant with operational speed increasing. Therefore, this has become one of the key factors which limits the operational speed and service life of key components. Wire misalignment, structural errors and uneven mass distribution of the catenary can further deteriorate the contact stability. In order to achieve a higher speed on existing lines, the catenary needs large-scale modification implying long out-off-service time. From the designing aspect, all components directly fixed to the catenary, like clamps, steady arms and other fittings, are made as light and small as possible to minimize disturbances. However, in other engineering applications, some well-designed additional mass systems are adopted aiming to improve their dynamic performance. In order to take advantage of these unavoidable masses on the catenary, an investigation on lumped-mass distribution in single-pantograph and multi-pantograph operations is performed with help of a 3D pantograph-catenary finite element (FE) model. The results show that a rightly-tuned mass, here the implementing location and the elasticity of its connection, can positively change the dynamic performance without implementing large-scale modification to the existing system. Through a brief discussion on the mechanism of this positive effect, this paper proposes that applying some artificial tuned-mass system can be a possible method to overcome unfavourable working conditions or even allow speed increase on existing lines.

J. Jimenez, J. M. Navarro, G. López et al.

In a more and more urbanized World, the so-called Smart Cities need to be driven by the principles of efficiency and sustainability. Information and Communications Technologies and, in particular, the Internet of Things will play a key role on this, since they will allow monitoring and optimizing all the municipal services that exist and shall exist. People flow monitoring stands out in this context due to its wide range of applications, spanning from monitoring transport infrastructure to physical security applications. There are different techniques to perform people flow monitoring, presenting pros and cons, as in any other engineering problem. Typically, the options that provide the most accurate results are also the most expensive ones, whereas there are cases where presence detection in given areas is enough and cost is a limiting factor. The main goal of this paper is to prove that a minimal deployment of sensors, combined with the adequate analysis and visualization algorithms, can render useful results. In order to achieve this goal, a dataset is used with 1-year data from a real infrastructure composed of 9 Wi-Fi tracking sensors deployed in the Telecommunications Engineering School of Universidad Politécnica de Madrid, which is visited by 4000 people daily and covers 1.8 hectares. The data analysis includes time and occupancy, position of people, and identification of common behaviors, as well as a comparison of the accuracy of the considered solution with actual data and a video monitoring system available at the library of the school. The obtained insights can be used for optimizing the management and operation of the school, as well as for other similar infrastructures and, in general, for other kind of applications which require not very accurate people flow monitoring at low cost.

Vladimír Soldán, Luboš Janko

ATFM - Uspořádání toku letového provozu je organizovaná služba, která je součástí služeb v rámci Air Traffic Management (ATM). Tato služba je poskytována letadlům a leteckým společnostem v zájmu zajištění řízeného, bezpečného, ekonomického a pravidelného letového provozu. Do procesu řízení letů vstupují nejrůznější faktory, ať se již jedná o vlivy očekávané nebo nahodilé. S těmito vlivy, zejména negativními, které působí na leteckou dopravu, se musí počítat. Proto vnímáme ATFM jako nástroj ke snižování účinku těchto vlivů, případně k jejich maximální eliminaci. Uspořádání toku letového provozu ATFM si můžeme představit jako koordinovanou činnost jednotlivců nebo provozních složek, zapojených do procesu letecké dopravy s cílem optimalizovat proces řízení letů. Výstupem z této činnosti je zajištění plynulého a bezpečného letového provozu.

HU Pinggui, WANG Peng

To assess the reliability of the DTECS-2 in working condition, stress-intensity models were used to deduce a formula for calculating using reliability. Based on vibration stepping test data and DTECS-2 actual vibration environment data, reliability degree of DTECS-2 in actual vibration environment was obtained, which was 0.997 3.

M. Rabe, A. Juan, N. Mustafee et al.

S. R. T. A. Grasselli, J. Andersson, A. Lehman et al.

Zhengboyang Gao, M. Dersch, Y. Qian et al.

LI Ming, LIU Nan, SHI Junjie

To improve comprehensive utilization efficiency of tramcar energy, influencing factors for tramcar running energy consumption influenced by the infrastructure and operation organization was analyzed, and the corresponding energy saving measures was put forward from aspects of the train properties, line condition, operation organization mode and others. On this basis, the impacting relationship between the running energy consumption and some key parameters was obtained by formula fitting under different speeds, which provided a feasible method for rapid assessment of tramcar running energy consumption.