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Journal articles on the topic 'Trains'
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1
Adamu, A., J. Zhang, F. Gidado, and F. Wang. "An Investigation of Influence of Windshield Configuration and Train Length on High-Speed Train Aerodynamic Performance." Journal of Applied Fluid Mechanics 16, no. 2 (February 1, 2023): 337–52. http://dx.doi.org/10.47176/jafm.16.02.1433.
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The aerodynamic performance of four train models with different windshield configurations (i.e., internal and/or external) in three train marshalling modes (i.e., 3, 6 and 8-car groups) was numerically investigated in this study. The train's airflow characteristics at Re=2.25×106 were determined using the shear stress transport (SST) k- turbulence model. The results were validated by comparing the pressure distributions and drag forces on the streamlined heads with experimental data. The difference in windshield configuration and train length has a substantial influence on the train’s flow field and surface pressure distribution. For the trains with internal windshields, due to non-uniform geometry, the flow is separated and vortices are formed at the windshield area. The boundary layer profile increases with the increased train length, and its thickness varies with windshield configurations. Asymmetric vortices are formed in the wake at a distance close to the tail car’s nose, except for trains with external windshields. The reduction of the flow velocity as the train length increases causes a reduction of the low pressure near the tail car’s streamline transition, thus causing a decrease in the tail car’s drag and lift forces. Consequently, for trains with external windshields, the head car’s drag increases, whereas the total train drag reduces significantly as the train length increases. Therefore, employing external windshields in all the inter-carriage gap sections, irrespective of the train length, demonstrates a good ability to reduce future train’s aerodynamic drag.
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Chen, Kaixin. "The Research of the Fluid Dynamics of Trains." Highlights in Science, Engineering and Technology 37 (March 18, 2023): 299–308. http://dx.doi.org/10.54097/hset.v37i.6085.
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Trains have been the main means of transportation in the world for a long time. Therefore, the progress and design of trains has been a widely debated topic, and how to reduce the wear and tear of trains is a major aspect. There are many factors that can affect the resistance of a train as it moves. Including but not limited to Locomotive shape, the smoothness of the connections between the carriages of a train, the wheel axle and the adsorption device under the train and the train’s relative velocity with respect to air. This paper will study two main aspects of train fluid resistance. The first is the locomotive shape, that is, the effect of differences in the external shape of the train on the surrounding fluid. The other is the speed of the train, which is the influence of the relative speed of the train and the surrounding air flow on the surrounding fluid.
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Verbytskyy, Volodymyr, Vitaly Minakov, Yevhen Misko, and Oleksandr Razboinikov. "Analysis of the construction of a port-storm mathematical model of a articulated two-link road train regarding the vertical storage." Ukrainian Journal of Applied Economics and Technology 8, no. 2 (March 20, 2023): 165–72. http://dx.doi.org/10.36887/2415-8453-2023-2-24.
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The article considers possible ways of development and improvement of a flat mathematical model of the movement of an articulated two-link road train considering the track and bringing this model to a spatial model that could consider the change in vertical loads and the subsequent change in the lateral deflection forces, which affect the indicators of turning and controllability of the articulated vehicle. This article proposes constructing a spatial mathematical model of a two-link road train considering the vertical component. The authors consider the problems associated with the movement of a two-track train over uneven terrain and height differences that may occur on the track. They consider the gravitational force's influence on the train's movement and develop a mathematical model that describes this process. The article presents mathematical equations describing the direction of a two-track train in three-dimensional space. They consider the mass of the train, traction forces, air resistance, gravitational force, and reactions from the ground. The authors use numerical methods to solve these equations and conduct computer simulations to study train motion under various conditions. The results of the study demonstrate that the vertical component significantly impacts the movement of a two-track train. It can affect the train's speed, energy efficiency, and stability. The authors conclude with the need to consider the vertical component when building mathematical models of double-track road trains. This paper is essential for researchers and engineers developing and designing road trains. Considering the vertical part will help improve the accuracy of mathematical models and increase the efficiency of two-track road trains in actual operating conditions. The obtained results are essential for developing and improving control systems for two-track road trains, particularly in transport, logistics, and mobile robots. The proposed model can be used to optimize the traffic trajectory and improve the efficiency and safety of the operation of road trains in natural conditions. The proposed model is designed for circular stationary and transient modes of movement of an articulated road train with the possibility of conducting a comparative analysis with a full-scale experiment. Keywords: spatial mathematical model, circular modes, vertical oscillations, articulated train.
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Hyman, Mario, and Mohd Hasan Ali. "A Novel Model for Wind Turbines on Trains." Energies 15, no. 20 (October 15, 2022): 7629. http://dx.doi.org/10.3390/en15207629.
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Wind turbines that are consistently exposed to the air displaced by moving trains have a high potential for energy generation. Researchers have developed mathematical models to simulate wind energy generation from turbines on moving trains but there are significant gaps in the developed model theory. Most models do not consider the negative effects that additional aerodynamic drag, increased weight, and modified dimensions can have on the train’s operation. To overcome the drawbacks of existing models, this work proposes a novel approach of modeling the wind turbines on trains by considering wind turbine exposure only when the train is decelerating or stationary. There are no models that consider all of these realistic physical effects as a function of time. Real-time analysis and power-system simulations showed that the proposed model could produce over 3 MJ of net energy for favorable train trips. The simulated load profile met the demand of a 1 KW generator connected to onboard electrical components. Some recommendations on possible future research on wind turbines on trains are explained.
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Kuszmaul, William. "Train tracks with gaps: Applying the probabilistic method to trains." Theoretical Computer Science 899 (January 2022): 39–47. http://dx.doi.org/10.1016/j.tcs.2021.11.017.
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Shao, Jing Jing, Lei Shan Zhou, Zi Xi Bai, and Yong Feng Shang. "Determination of the Minimum Departure Interval between Trains with same High-Speed at the Relatively Initial Station." Applied Mechanics and Materials 587-589 (July 2014): 1737–40. http://dx.doi.org/10.4028/www.scientific.net/amm.587-589.1737.
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Chinese high-speed railway is in a boom and making train diagram with high-density trains to relieve capacity intense and improve operational efficiency has become the research focus. Different kinds of station intervals between adjacent trains are the basis for the train diagram. According to the situation in which trains with different speed run on the same line and the proportion of high-speed trains is much larger than that of middle-speed trains, this paper raises principles and methods to determine the minimum departure interval between trains with same speed at the relatively initial station. The minimum departure interval between trains with same speed at the relatively initial station is a necessary and sufficient condition for making train diagram since there is no overtaking between same-speed trains.
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Li, Yongle, Jiangtao Deng, Bin Wang, and Chuanjin Yu. "Running Safety of Trains under Vessel-Bridge Collision." Shock and Vibration 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/252574.
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To optimize the sensor placement of the health monitoring system, the dynamic behavior of the train-bridge system subjected to vessel-collision should be studied in detail firstly. This study thus focuses on the characteristics of a train-bridge system under vessel-bridge collision. The process of the vessel-bridge collision is simulated numerically with a reliable finite element model (FEM). The dynamic responses of a single car and a train crossing a cable-stayed bridge are calculated. It is shown that the collision causes significant increase of the train’s lateral acceleration, lateral wheelset force, wheel unloading rate, and derailment coefficient. The effect of the collision on the train’s vertical acceleration is much smaller. In addition, parametric studies with various train’s positions, ship tonnage, and train speed are performed. If the train is closer to the vessel-bridge collision position or the ship tonnage is larger, the train will be more dangerous. There is a relatively high probability of running danger at a low speed, resulting from longer stay of the train on the bridge. The train’s position, the ship tonnage, and the train speed must be considered when determining the most adverse conditions for the trains running on bridges under vessel-bridge collision.
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Yang, Lu, Leishan Zhou, Hanxiao Zhou, Chang Han, and Wenqiang Zhao. "A Lagrangian Method for Calculation of Passing Capacity on a Railway Hub Station." Mathematics 11, no. 6 (March 15, 2023): 1418. http://dx.doi.org/10.3390/math11061418.
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This research paper proposes a Lagrangian method to address the passing capacity of the calculation problem (PCCP) for a hub station in a high-speed railway (HSR) system. The passing capacity of a hub station is critical for determining the train timetable and maximizing the number of trains that can operate on different lines. The objective of this study is to determine the maximum number of trains that can pass through, start at, or end at a hub station. To achieve this objective, a mathematical model was introduced to solve the PCCP. The model was decomposed into two parts using a Lagrangian relaxation algorithm. The first part of the model was a simple train arrival problem (TAP) that reflected the timing of trains at the hub station with simultaneous arrival and departure time constraints. The second part of the model was a train spatio-temporal routing problem (TSRP) that aimed to solve the shortest spatio-temporal path of trains with free conflict with the train’s trajectory. A real instance was provided to demonstrate the feasibility of the proposed approach and the effectiveness of the Lagrangian method. The results showed that the proposed method can efficiently solve the PCCP and maximize the passing capacity of a hub station in an HSR system.
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Vakulenko, S. P., and P. A. Kozlov. "Optimization of Locomotives’ Turnover with a «Labyrinth» System." World of Transport and Transportation 14, no. 4 (August 28, 2016): 92–104. http://dx.doi.org/10.30932/1992-3252-2016-14-4-10.
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The problem of rational use of locomotives is quite acute. Here it is necessary to find the best compromise. In case of excess of locomotives there are less delays of trains, but locomotive costs are higher. In case of insufficient number of locomotives the situation is reversed. A model for calculating the optimal modes of turnover of train locomotives serving train flow isтoffered. The model promotes the further development of the dynamic transport task. The parameters of trains movement and the use of locomotives are provided, work schedules for each of them are built. The impact of the number of locomotives on the train’s mobility is estimated.
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Hou, Tao, Li Tang, Hongxia Niu, and Tingyang Zhao. "Research on speed control of high-speed trains based on hybrid modeling." Archives of Transport 66, no. 2 (June 30, 2023): 77–87. http://dx.doi.org/10.5604/01.3001.0016.3132.
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With the continuous improvement of train speed, the automatic driving of trains instead of driver driving has become the development direction of rail transit in order to realize traffic automation. The application of single modeling methods for speed control in the automatic operation of high-speed trains lacks exploration of the com-bination of train operation data information and physical model, resulting in low system modeling accuracy, which impacts the effectiveness of speed control and the operation of high-speed trains. To further increase the dynamic modeling accuracy of high-speed train operation and the high-speed train's speed control effect, a high-speed train speed control method based on hybrid modeling of mechanism and data drive is put forward. Firstly, a model of the high-speed train's mechanism was created by analyzing the train's dynamics. Secondly, the improved kernel-principal component regression algorithm was used to create a data-driven model using the actual opera-tion data of the CRH3 (China Railway High-speed 3) high-speed train from Huashan North Railway Station to Xi'an North Railway Station of "Zhengxi High-speed Railway," completing the mechanism model compensation and the error correction of the speed of the actual operation process of the high-speed train, and realizing the hybrid modeling of mechanism and data-driven. Finally, the prediction Fuzzy PID control algorithm was devel-oped based on the natural line and train characteristics to complete the train speed control simulation under the hybrid model and the mechanism model, respectively. In addition, analysis and comparison analysis were conduct-ed. The results indicate that, compared to the high-speed train speed control based on the mechanism model, the high-speed train speed control based on hybrid modeling is more accurate, with an average speed control error reduced by 69.42%. This can effectively reduce the speed control error, improve the speed control effect and oper-ation efficiency, and demonstrate the efficacy of the hybrid modeling and algorithm. The research results can provide a new ideal of multi-model fusion modeling for the dynamic modeling of high-speed train operation, further improve control objectives such as safety, comfort, and efficiency of high-speed train operation, and pro-vide a reference for automatic driving and intelligent driving of high-speed trains.
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Haslinger, Robert, Kristina Lisa Klinkner, and Cosma Rohilla Shalizi. "The Computational Structure of Spike Trains." Neural Computation 22, no. 1 (January 2010): 121–57. http://dx.doi.org/10.1162/neco.2009.12-07-678.
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Neurons perform computations, and convey the results of those computations through the statistical structure of their output spike trains. Here we present a practical method, grounded in the information-theoretic analysis of prediction, for inferring a minimal representation of that structure and for characterizing its complexity. Starting from spike trains, our approach finds their causal state models (CSMs), the minimal hidden Markov models or stochastic automata capable of generating statistically identical time series. We then use these CSMs to objectively quantify both the generalizable structure and the idiosyncratic randomness of the spike train. Specifically, we show that the expected algorithmic information content (the information needed to describe the spike train exactly) can be split into three parts describing (1) the time-invariant structure (complexity) of the minimal spike-generating process, which describes the spike train statistically; (2) the randomness (internal entropy rate) of the minimal spike-generating process; and (3) a residual pure noise term not described by the minimal spike-generating process. We use CSMs to approximate each of these quantities. The CSMs are inferred nonparametrically from the data, making only mild regularity assumptions, via the causal state splitting reconstruction algorithm. The methods presented here complement more traditional spike train analyses by describing not only spiking probability and spike train entropy, but also the complexity of a spike train's structure. We demonstrate our approach using both simulated spike trains and experimental data recorded in rat barrel cortex during vibrissa stimulation.
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Dick, C. Tyler, Ivan Atanassov, F. Bradford Kippen, and Darkhan Mussanov. "Relative train length and the infrastructure required to mitigate delays from operating combinations of normal and over-length freight trains on single-track railway lines in North America." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 7 (November 19, 2018): 731–42. http://dx.doi.org/10.1177/0954409718809204.
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Distributed power locomotives have facilitated longer heavy-haul freight trains that improve the efficiency of railway operations. In North America, where the majority of mainlines are single track, the potential operational and economic advantages of long trains are limited by the inadequate length of many existing passing sidings (passing loops). To alleviate the challenge of operating trains that exceed the length of passing sidings, railways preserve the mainline capacity by extending passing sidings. However, industry practitioners rarely optimize the extent of infrastructure investment for the volume of over-length train traffic on a particular route. This paper investigates how different combinations of normal and over-length trains, and their relative lengths, relate to the number of siding extensions necessary to mitigate the delay performance of over-length train operation on a single-track rail corridor. The experiments used Rail Traffic Controller simulation software to determine train delay for various combinations of short and long train lengths under different directional distributions of a given daily railcar throughput volume. Simulation results suggest a relationship between the ratio of train lengths and the infrastructure expansion required to eliminate the delay introduced by operating over-length trains on the initial route. Over-length trains exhibit delay benefits from siding extensions while short trains are relatively insensitive to the expanded infrastructure. Assigning directional preference to over-length trains improves the overall average long-train delay at the expense of delay to short trains. These results will allow railway practitioners to make more informed decisions on the optimal incremental capital expansion strategy for the operation of over-length trains.
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Li, Weixi, Geordie S. Roscoe, Zhipeng Zhang, M. Rapik Saat, and Christopher P. L. Barkan. "Quantitative Analysis of the Derailment Characteristics of Loaded and Empty Unit Trains." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 10 (November 29, 2018): 156–65. http://dx.doi.org/10.1177/0361198118810780.
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Operation of unit trains has grown substantially over the past half century owing to their ability to provide economic and efficient transportation of bulk products. Although various aspects of train safety have been studied, there has been limited research examining the effect of train loading conditions on derailment occurrence, cause and severity. An algorithm was developed to identify derailments of loaded and empty unit trains on mainlines and sidings recorded in the Federal Railroad Administration database. A dataset of these accidents for the 15-year period of 2001–2015 was developed and analyzed. The frequency of derailments for both loaded and empty unit trains declined by more than 50%. The average number of cars derailed per accident fluctuated for both loading conditions, but showed no particular trend. Approximately five times more loaded unit train derailments were recorded in the database than empty unit trains, but in the absence of specific unit train traffic data, inferences about rates are not possible. Loaded unit trains were more than four times heavier than empty unit trains and loaded train derailments tended to involve more cars than empty trains. The distribution of derailment causes differed for loaded and empty unit trains. Loaded trains most frequently derailed because of broken rails and welds, while the leading cause of empty train derailments was obstructions, in particular severe weather. Over 90% of the derailments of loaded and empty unit trains considered in this study occurred on mainline tracks, and the distribution of causes differed between mainline and siding tracks.
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Tian, Chun, Meng Ling Wu, Yang Yong Zhu, and Meng Ting Chen. "Running Safety of High-Speed Train Equipped with Aerodynamic Brake under Cross Wind." Advanced Materials Research 614-615 (December 2012): 348–54. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.348.
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The flow field structure and aerodynamic forces of trains with aerodynamic brake in cross-wind after simplifying the train’s model are studied. Three-dimensional Reynolds average N-S equations (RANS) combining k-ω turbulence model is adopted. The SIMPLE method is used to couple the pressure and velocity. Firstly, the train’s flow field’s variation discipline caused by the aerodynamic brake is analyzed. Then the side force, lift force and rollover moment acting on the train with aerodynamic brake and the one without aerodynamic brake are compared on condition of various wind direction angles. The influence of the aerodynamic brake on trains’ aerodynamic forces and derailment coefficient on condition of various wind direction are analysed. It comes to a conclusion that the derailment coefficient of the train with aerodynamic braking is truly increased but only slightly increased and all the derailment coefficients are under 0.8 which satisfy the safety request of the train’s running safety.
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GODWIN, T., RAM GOPALAN, and T. T. NARENDRAN. "FREIGHT TRAIN ROUTING AND SCHEDULING IN A PASSENGER RAIL NETWORK: COMPUTATIONAL COMPLEXITY AND THE STEPWISE DISPATCHING HEURISTIC." Asia-Pacific Journal of Operational Research 24, no. 04 (August 2007): 499–533. http://dx.doi.org/10.1142/s0217595907001358.
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In many countries, freight trains have to share a rail network with passenger trains. In this paper, we consider a situation where passenger trains must adhere to a strict published schedule, whereas freight train movements can be inserted at any convenient time, without disrupting scheduled passenger trains. We propose an algorithm for the problem of routing and scheduling of a single freight train in a passenger rail network. However, the multiple freight train routing and scheduling problem is shown to be NP-complete, even for simplified instances. Specifically, we show that both routing and scheduling of freight trains are difficult, even when only two freight trains are considered. It is also difficult when freight train movements are restricted to reach their destinations with no idling permitted at intermediate stations. We have developed a Stepwise Dispatching Heuristic for routing and scheduling multiple freight trains in a passenger rail network. Computational results confirm the efficacy of our algorithm for single freight train routing and of the proposed Stepwise Dispatching Heuristic.
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Lai, Yung-Cheng (Rex), and Christopher P. L. Barkan. "Options for Improving the Energy Efficiency of Intermodal Freight Trains." Transportation Research Record: Journal of the Transportation Research Board 1916, no. 1 (January 2005): 47–55. http://dx.doi.org/10.1177/0361198105191600108.
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Intermodal trains are typically the fastest trains operated by North American freight railroads. Ironically, these trains tend to have the poorest aerodynamic characteristics. Because of constraints imposed by equipment design and diversity, intermodal trains incur greater aerodynamic penalties and increased fuel consumption than other trains. Improving the loading patterns of intermodal trains has the potential to improve aerodynamic characteristics and thus fuel efficiency. Train aerodynamics and resistance analyses were conducted on several alternative intermodal train-loading configurations. Matching intermodal loads with cars of an appropriate length reduces the gap length between loads and thereby improves airflow. Filling empty slots with empty containers or trailers also reduces aerodynamic resistance and improves energy efficiency, despite the additional weight penalty and consequent increase in bearing and rolling resistance. Depending on the particular train configuration, train resistance can be lowered by as much as 27% and fuel savings by 1 gal/mi per train.
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Yang, Junxia, and Youpeng Zhang. "Adaptive Cooperative Control of Multiple Urban Rail Trains with Position Output Constraints." Algorithms 15, no. 5 (April 21, 2022): 138. http://dx.doi.org/10.3390/a15050138.
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This paper studies the distributed adaptive cooperative control of multiple urban rail trains with position output constraints and uncertain parameters. Based on an ordered set of trains running on the route, a dynamic multiple trains movement model is constructed to capture the dynamic evolution of the trains in actual operation. Aiming at the position constraints and uncertainties in the system, different distributed adaptive control algorithms are designed for all trains by using the local information about the position, speed and acceleration of the train operation, so that each train can dynamically adjust its speed through communicating with its neighboring trains. This control algorithm for each train is designed to track the desired position and speed curve, and the headway distance between any two neighboring trains is stable within a preset safety range, which guarantee the safety of tracking operation of multiple urban rail trains. Finally, the effectiveness of the designed scheme is verified by numerical examples.
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Liao, Zhengwen. "Rescheduling Out-of-Gauge Trains with Speed Restrictions and Temporal Blockades on the Opposite-Direction Track." Mathematics 11, no. 12 (June 11, 2023): 2659. http://dx.doi.org/10.3390/math11122659.
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Out-of-gauge trains are trains with loading freight that exceeds the loading limitation border. Considering collision avoidance, the out-of-gauge trains have speed restriction of their own, and the trains running on the parallel track. Therefore, it is necessary to execute a train rescheduling procedure to rearrange the train paths of the out-of-gauge trains and the affected trains based on the fundamental timetable. For rescheduling the timetable, considering the blockades and the speed restrictions caused by the out-of-gauge trains, this paper proposed a time-space-state network representation for describing the out-of-gauge train rescheduling problem. A novel concept, speed allowance, is introduced to describe the train speed restriction due to the out-of-gauge trains. An integer programming model based on the time-space network is proposed to minimize the total train delay when running the out-of-gauge trains. The model can be solved by the rolling-time horizon approach for reducing computational time. A numerical example is conducted based on the conventional railway in China, demonstrating the solution performance of the model and the practical use of the methodology. Gurobi solver cannot obtain an optimal solution within 1 h when the planning-time horizon is greater than 120 min. With the rolling-time horizon approach, the rescheduled timetable can be obtained within 124 s for the 300 min planning-time horizon using 180 min rolling-time window.
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Soper, David, and Chris Baker. "A full-scale experimental investigation of passenger and freight train aerodynamics." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 5 (May 6, 2019): 482–97. http://dx.doi.org/10.1177/0954409719844431.
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The movement of a train creates a disturbance to the air through which it passes, known as a slipstream. Such disturbances are characterised by changes in pressure, notably around the vehicle nose/tail, and a highly turbulent boundary growth along the vehicle side with an increasing slipstream velocity magnitude. Although these characteristic features occur in some form for all trains, the flow development associated with various train types can often be very different. Variability in train type makes it difficult to accurately characterise the aerodynamic effects of each individual train. In this paper, a detailed set of tests are undertaken to assess the aerodynamic flow development created around various train types common to the UK railway network. A comparison of the analysed data from different passenger and freight trains was made. The variability of freight train results was larger in comparison to the passenger trains examined, because of the large flow separations around the bluff freight train. Although the speed was lower for freight trains, the slipstream velocity and pressure magnitudes were larger than those observed for passenger trains. Passenger trains could be divided aerodynamically into two main types: long distance passenger trains and commuter trains. Longer train lengths were shown to increase the boundary layer growth: an important feature for long distance passenger trains as it creates an increase in the slipstream velocity peak magnitude at the train tail. Boundary layer stabilisation is not observed as in previous studies. The coupling of two carriage sets together, creating a large V-shaped region at the centre of the train, led to a clear step slipstream velocity peak coinciding with the change in pressure at the coupling region. Cross-correlation of results from measuring positions within the characteristic turbulent length scale range appeared to show similar results to autocorrelation time scales for larger scale separation of turbulent structures from the bogie and inter-carriage regions.
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Levin, D. Yu. "Train Formation Management. Part 1." World of Transport and Transportation 20, no. 1 (December 17, 2022): 96–104. http://dx.doi.org/10.30932/1992-3252-2022-20-1-11.
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Long-term regulatory and technological documents related to train formation are often so far from the changing actual operational situation that more trains are being formed than can be provided with locomotives and sent from the station in a timely manner, sections are oversaturated with trains, stations operate with an excess of car fleet, etc. Such unpredictable situations result in unproductive delays of trains, increase the goods delivery time, reduce the use of transit, transportation, and processing capacity of railways. At the same time, reducing the time of validity of regulatory and technological documents can significantly increase the efficiency of operational management of the transportation process. The purpose of the article is to show how the operational management of train formation instead of the passive uncontrolled process of accumulation of trains at marshalling yards expands the possibilities of the train formation plan, eliminates uncertainty and creates optimal conditions for train, marshalling and freight operations.Changes in management of train formation, which are put forward on the basis of generalisation of a number of results of earlier author’s studies and publications and newly formulated proposals for discussion, will make it possible to manage the transportation process in a fundamentally new way: to form such a number of trains that will be provided in a timely manner with locomotives and «threads» of the train schedule; send such a number of trains from the train assembling stations that will not lead to oversaturation of sections with trains; to ensure the arrival of such a number of trains at marshalling yards that will allow them to work in the optimal mode; to ensure the parity of arrivals of even and odd trains at locomotive change stations; to help in a timely manner with the selection of wagons cars in case of difficulties in the work of freight stations, etc. [1].
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Cheng, Shiquan, Jianmin Ge, Longhua Ju, and Yuhao Chen. "Prediction Model for the Environmental Noise Distribution of High-Speed Maglev Trains Using a Segmented Line Source Approach." Applied Sciences 15, no. 8 (April 10, 2025): 4184. https://doi.org/10.3390/app15084184.
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Based on the theory of uniform finite-length incoherent line source radiation and real vehicle online test data of Shanghai Maglev trains, a prediction model for environmental noise is established using an equivalent segmented line sound source approach. The noise produced by Shanghai high-speed Maglev trains running at speeds of 235, 300, and 430 km/h is tested and analyzed using microphones. The test data are combined with computational fluid dynamics simulations to divide the train’s sound sources equally into five sections. Theoretical calculations are carried out on the noise test data collected as the train passes by, and the source strength of each individual sub-sound source during the train operation is determined using the least-squares method. As a result, a prediction model for the environmental noise of high-speed Maglev trains, represented as a combination of multiple sources, is developed. The predicted results are compared with the measured values to validate the accuracy of the model. The proposed model can be used for environmental assessments before new train lines are launched, allowing for appropriate mitigation measures to be taken in advance to reduce the impact of Maglev noise on the surrounding residential and ecological environments.
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Jobin, Raymond A. "Trains, Tracks, and Nodal Regions." Journal of Geography 90, no. 4 (July 1991): 160–63. http://dx.doi.org/10.1080/00221349108979292.
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Shayak, B. "Why trains stay on tracks." American Journal of Physics 85, no. 3 (March 2017): 178–84. http://dx.doi.org/10.1119/1.4973370.
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Pan, Wenbo, Xianghua Fan, Hongbo Li, and Kai He. "Long-Range Perception System for Road Boundaries and Objects Detection in Trains." Remote Sensing 15, no. 14 (July 10, 2023): 3473. http://dx.doi.org/10.3390/rs15143473.
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This article introduces a long-range sensing system based on millimeter-wave radar, which is used to detect the roadside boundaries and track trains for trains. Due to the high speed and long braking distance of trains, existing commercial vehicle sensing solutions cannot meet their needs for long-range target detection. To address this challenge, this study proposes a long-range perception system for detecting road boundaries and trains based on millimeter-wave radar. The system uses high-resolution, long-range millimeter-wave radar customized for the strong scattering environment of rail transit. First, we established a multipath scattering theory in complex scenes such as track tunnels and fences and used the azimuth scattering characteristics to eliminate false detections. A set of accurate calculation methods of the train’s ego-velocity is proposed, which divides the radar detection point clouds into static target point clouds and dynamic target point clouds based on the ego-velocity of the train. We then used the road boundary curvature, global geometric parallel information, and multi-frame information fusion to extract and fit the boundary in the static target point stably. Finally, we performed clustering and shape estimation on the radar track information to identify the train and judge the collision risk based on the position and speed of the detected train and the extracted boundary information. The paper makes a significant contribution by establishing a multipath scattering theory for complex scenes of rail transit to eliminate radar false detection and proposing a train speed estimation strategy and a road boundary feature point extraction method that adapt to the rail environment. As well as building a perception system and installing it on the train for verification, the main line test results showed that the system can reliably detect the road boundary more than 400 m ahead of the train and can stably detect and track the train.
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Liu, Xiang. "Risk Comparison of Transporting Hazardous Materials in Unit Trains versus Mixed Trains." Transportation Research Record: Journal of the Transportation Research Board 2608, no. 1 (January 2017): 134–42. http://dx.doi.org/10.3141/2608-15.
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This research developed an integrated, generalized risk analysis methodology for comparing hazardous materials transportation risk in unit trains versus mixed trains for the same amount of traffic demand. The risk methodology accounted for FRA track class, method of operation, annual traffic density, train length, speed, point of derailment, the number and placement of tank cars in a train, tank car placement, tank car safety design, and population density along the rail line. With these inputs, the methodology estimates train derailment rate, the probability of tank car derailment and release, and release consequence by train configuration. The analysis showed that tank car positions could affect the risk comparison between unit trains and mixed trains in transporting hazardous materials. In particular, if all tank cars were in positions that were least prone to derailment, distributing tank cars to many unit trains could reduce the overall risk. Otherwise, consolidating tank cars into unit trains could lead to a lower risk. The methodology has been implemented in a computer-aided decision support tool that automatically calculates the risk values for various track, rolling stock, and operational characteristics.
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Yoon, Hyuk-Jin, Su-Hwan Yun, Dae-Hyun Kim, Jae Hee Kim, Bong-Kwan Cho, Gi-Gun Lee, Soon-Eung Park, and Young-Chul Kim. "Effect of High-Speed Train-Induced Wind on Trackside UAV Thrust Near Railway Bridge." Applied Sciences 10, no. 10 (May 18, 2020): 3495. http://dx.doi.org/10.3390/app10103495.
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Imaging devices attached to unmanned aerial vehicles (UAVs) are used for crack measurements of railway bridges constructed for high-speed trains. This research aims to investigate track-side wind induced by high-speed trains and its effect on UAV thrust near the railway bridge. Furthermore, the characteristics of train-induced wind in three axial directions along a track, wind velocity, and the effect of train-induced wind on the UAV thrust were analyzed. This was achieved by installing 3-axis ultrasonic anemometers and a UAV thrust measurement system on top of a PSC box girder bridge. The changes in the train-induced wind velocity were monitored along the train travel, width, and height directions. The train-induced wind was measured at distances of 0.8, 1.3, 2.3, and 2.8 m away from the train’s body to analyze wind velocity based on distance. It was found that the maximum wind velocity decreased linearly as the distance from the train’s body increased. The UAV thrust increased by up to 20% and 60%, owing to train-induced wind when the leading and trailing power cars of a high-speed train passed, respectively. Thus, it is necessary to conduct further research to develop robust control and a variable pitch-propeller that can control thrust.
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Ostendorf, Carel. "The effect of two trains passing at the same time on the ground borne vibration level." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 2 (August 1, 2021): 4832–42. http://dx.doi.org/10.3397/in-2021-2853.
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When predicting the ground borne vibration level, it is assumed that only one train passes so the predicted vibration level is caused by a single train. When there is one track for every direction of the train, it is possible that two trains will pass each other on a specific location at the same time. What influence do these two trains have on the vibration level compared to the vibration level of a single train passing that same location? For this study ground borne vibration levels have been measured on two locations in The Netherlands using a 3 by 3 grid, 25 meters apart, on a distance of 25, 50 and 75 meters of the track. During the 4 weeks measuring time, all the trains have been captured on video. All the double train situations have been marked. The corresponding vibration level Vmax (according to the Dutch SBR B guideline) has been determined for both the single trains and the double trains and compared to each other. In the analysis, the type of trains passing each other and the distance of the receiver to the track, has been taken into account when determining the difference in vibration level.
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Xu, Ruxun, Jianjun Meng, Juhui Zhang, Xiaoqiang Chen, and Decang Li. "Following Consistency of Energy-Saving Operation for Urban Rail Trains Based on Event Triggering Mechanism." Discrete Dynamics in Nature and Society 2022 (December 8, 2022): 1–15. http://dx.doi.org/10.1155/2022/3790548.
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To reduce the traction energy consumption of urban rail trains by regenerating energy, a train traction and braking model was designed based on algebraic graph theory and train dynamics theory and the following consistency model of energy-saving operation of urban rail trains was constructed based on the conditions of the coordination coefficient and the operating condition conversion of trains. Not only to constantly update the consistency controller and save communication resources but also to optimize the energy-saving effect, the consistency algorithm of event triggering was used to search for the optimal operating conditions of trains and the energy-saving operation scheme for multiple trains was established. Taking the train diagram of a subway line in Jinan as an example, the energy-saving control scheme of four trains was solved by MATLAB simulation. The simulation results show that the model can not only ensure parking accuracy and punctuality but also energy savings effectively; that is, the proportion of the total regenerative energy used by the follower train in the actual energy consumption is increased from 3.32% to 10.76%, and the actual total energy consumption of the train is reduced by 9.23%.
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Masharipov, Masud, Abdulaziz Gulamov, Marufdjan Rasulov, Shinpolat Suyunbayev, Nazdana Adilova, and Mukhammadaziz Rasulmukhammedov. "Development of enhanced method for planning train locomotives ready to operate the next day." E3S Web of Conferences 458 (2023): 03009. http://dx.doi.org/10.1051/e3sconf/202345803009.
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A series of methods for planning the use of train locomotives has been developed. However, existing scientific research does not clearly specify how the arrival and departure times of freight trains are determined in train schedules, and locomotives are assigned to trains based on the condition of “Locomotive waits for train”. This article proposes a methodology for determining the average time of stay for train locomotives and trains at the boundaries of train sidings for all scenarios ranging from the condition of “Train waits for locomotive” to “Locomotive waits for train”. The EGM program has been developed and created for calculating the fleet of freight locomotives based on the graphical movement time of trains, and an enhanced method for planning the effective use of train locomotives has been developed based on minimizing the downtime of rolling stock within the boundaries of towing sidings.
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Li, Weibin, Yuejun Wang, Yunquan Hao, Wei Zhao, and Yanlin Zhang. "Analysis of Aerodynamic Characteristics of High-speed Train with Asymmetric Heads." Journal of Physics: Conference Series 2280, no. 1 (June 1, 2022): 012004. http://dx.doi.org/10.1088/1742-6596/2280/1/012004.
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Abstract High-speed transportation is closely related to people’s livelihood and national economy, so it becomes an important development aspect to the whole country. The safety, comfort and economy of high-speed train are the key consideration during its design process. In the future, new trains and old ones will be used for a long time, and the performance of new trains which run on the old lines may be limited. These situations make the research of high-speed train with asymmetric heads much necessary. Aiming at the feasibility of the train with asymmetric heads, the heads of train CRH3 and another typical train with a similar speed are selected. Based on the two heads, the digital models of the traditional trains with symmetric heads and the new trains with asymmetric heads are built firstly. And then their aerodynamic characteristics are computed by the SIMPLE method. In the numerical part, the performances of the trains are compared on the condition without crosswind, which shows that one of the new trains with asymmetric heads is the best among them. Moreover, the aerodynamic characteristics of this new model under crosswind is analyzed, which demonstrates that the train with asymmetric heads is feasible. The research shows that the train with asymmetric heads can achieve better results through the proper aerodynamic shape optimization design, which presents an idea for the future high-speed train design.
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Li, Weibin, Yuejun Wang, Yunquan Hao, Wei Zhao, and Yanlin Zhang. "Analysis of Aerodynamic Characteristics of High-speed Train with Asymmetric Heads." Journal of Physics: Conference Series 2280, no. 1 (June 1, 2022): 012004. http://dx.doi.org/10.1088/1742-6596/2280/1/012004.
Full textAbstract:
Abstract High-speed transportation is closely related to people’s livelihood and national economy, so it becomes an important development aspect to the whole country. The safety, comfort and economy of high-speed train are the key consideration during its design process. In the future, new trains and old ones will be used for a long time, and the performance of new trains which run on the old lines may be limited. These situations make the research of high-speed train with asymmetric heads much necessary. Aiming at the feasibility of the train with asymmetric heads, the heads of train CRH3 and another typical train with a similar speed are selected. Based on the two heads, the digital models of the traditional trains with symmetric heads and the new trains with asymmetric heads are built firstly. And then their aerodynamic characteristics are computed by the SIMPLE method. In the numerical part, the performances of the trains are compared on the condition without crosswind, which shows that one of the new trains with asymmetric heads is the best among them. Moreover, the aerodynamic characteristics of this new model under crosswind is analyzed, which demonstrates that the train with asymmetric heads is feasible. The research shows that the train with asymmetric heads can achieve better results through the proper aerodynamic shape optimization design, which presents an idea for the future high-speed train design.
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Zhou, Xinping, Yuandeng Shen, Yihua Yan, Ke Yu, Zhining Qu, Ahmed Ahmed Ibrahim, Zehao Tang, et al. "Broad and Bidirectional Narrow Quasiperiodic Fast-propagating Wave Trains Associated with a Filament-driven Halo Coronal Mass Ejection on 2023 April 21." Astrophysical Journal 968, no. 2 (June 1, 2024): 85. http://dx.doi.org/10.3847/1538-4357/ad4456.
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Abstract This paper presents three distinct wave trains that occurred on 2023 April 21: a broad quasiperiodic fast-propagating (QFP) wave train and bidirectional narrow QFP wave trains. The broad QFP wave train expands outward in a circular wave front, while bidirectional narrow QFP wave trains propagate in the northward and southward directions, respectively. The concurrent presence of the wave trains offers a remarkable opportunity to investigate their respective triggering mechanisms. Measurement shows that the speed of the broad QFP wave train is in the range of 300–1100 km s−1 in different propagating directions. There is a significant difference in the speed of the bidirectional narrow QFP wave trains: the southward propagation achieves 1400 km s−1, while the northward propagation only reaches about 550 km s−1 accompanied by a deceleration of about 1–2 km s−2. Using the wavelet analysis, we find that the periodicity of the propagating wave trains in the southward and northward directions closely matches the quasiperiodic pulsations exhibited by the flares. Based on these results, the narrow QFP wave trains were most likely excited by the intermittent energy release in the accompanying flare. In contrast, the broad QFP wave train had a tight relationship with the erupting filament, probably attributed to the unwinding motion of the erupting filament, or the leakage of the fast sausage wave train inside the filament body.
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Prokhorchenko, Andrii, Dmytro Gurin, Iryna Lahuta, and Viktoriia Sunytska. "IMPROVEMENT OF THE PROCEDURE FOR SEARCHING RATIONAL TIME RESERVES FOR RECOVERY OF TRAIN MOVEMENT OF DIFFERENT CATEGORIES." Collected scientific works of Ukrainian State University of Railway Transport, no. 193 (October 5, 2021): 44–53. http://dx.doi.org/10.18664/1994-7852.193.2020.229812.
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This article improves the procedure for finding rational time reserves for theresumption of trains of different categories depending on the number of detained trains on the basisof the epidemiological SIR-model. A modified epidemiological SIR-model has been implemented forthe experimental railway line, which allows to take into account the interaction of trains of differentpriorities in the train schedule and the possibility of resumption of delayed trains due to the set timereserve. The adjustment of the delay rate transfer coefficients on the real data of train delays at theline has been performed. The solution of the system of differential equations of the SIR-model isproposed to be performed by the numerical Runge-Kutta method of the 4th order. Experimentalstudies of the impact of passenger train delays on the reliability of the regulatory schedule havebeen conducted. Experimental studies of the impact of passenger train delays on the reliability ofthe regulatory schedule have been conducted. The dependences of the number of detained trains ofdifferent categories on the change in the amount of time reserve for the resumption of trains ofdifferent categories are obtained. Rational time reserves for passenger, suburban and freight trainshave been established. These results were expertly assessed and confirm the adequacy of theobtained decisions in the practice of developing a regulatory schedule of trains at JSCUkrzaliznytsia. The application of the proposed approach will automate the complex process offinding rational values of compensation time in the threads of trains of different categories on therailway line and, as a consequence, increase the level of reliability of the regulatory train schedule.
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Meng, Gaoyang, and Jianjun Meng. "Dynamics Performance Research and Calculation of Speed Threshold Curve for High-Speed Trains Under Unsteady Wind Loads." Mathematics 12, no. 23 (November 29, 2024): 3780. https://doi.org/10.3390/math12233780.
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Affected by strong wind environments, the vibration of trains will significantly intensify, which will severely impact the running quality of trains. To address such challenges, an improved wind load model is proposed in this paper to simulate the shock of strong wind on trains. The proposed model employs the integral approach to calculate the equivalent wind load on trains and applies it to the body of trains during the dynamics simulation process. Eventually, the two-level running quality threshold curve for passenger and freight trains is acquired through the conditional probability density function and the regularized regression model. This achievement covers train speed restrictions for wind speeds ranging from 0~25 m/s, providing a scientific basis for railway departments to adjust train speeds based on real-time wind speeds. It is of utmost importance for ensuring the safe and efficient operation of trains under strong wind conditions.
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Fayad, Ahmad, Hussein Ibrahim, Adrian Ilinca, Sasan Sattarpanah Karganroudi, and Mohamad Issa. "Energy Recovering Using Regenerative Braking in Diesel–Electric Passenger Trains: Economical and Technical Analysis of Fuel Savings and GHG Emission Reductions." Energies 15, no. 1 (December 21, 2021): 37. http://dx.doi.org/10.3390/en15010037.
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Rail transport, specifically diesel–electric trains, faces fundamental challenges in reducing fuel consumption to improve financial performance and reduce GHG emissions. One solution to improve energy efficiency is the electric brake regenerative technique. This technique was first applied on electric trains several years ago, but it is still considered to improve diesel–electric trains efficiency. Numerous parameters influence the detailed estimation of brake regenerative technique performance, which makes this process particularly difficult. This paper proposes a simplified energetic approach for a diesel–electric train with different storage systems to assess these performances. The feasibility and profitability of using a brake regenerative system depend on the quantity of energy that can be recuperated and stored during the train’s full and partial stop. Based on a simplified energetic calculation and cost estimation, we present a comprehensive and realistic calculation to evaluate ROI, net annual revenues, and GHG emission reduction. The feasibility of the solution is studied for different train journeys, and the most significant parameters affecting the impact of using this technique are identified. In addition, we study the influence of electric storage devices and low temperatures. The proposed method is validated using experimental results available in the literature showing that this technique resulted in annual energy savings of 3400 MWh for 34 trains, worth USD 425,000 in fuel savings.
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Su, Huanyin, Wencong Tao, and Xinlei Hu. "A Line Planning Approach for High-Speed Rail Networks with Time-Dependent Demand and Capacity Constraints." Mathematical Problems in Engineering 2019 (March 17, 2019): 1–18. http://dx.doi.org/10.1155/2019/7509586.
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In high-speed rail networks, trains are operated with high speeds and high frequencies, which can satisfy passenger demand with different expected departure times. Given time-dependent demand, this paper proposes a line planning approach with capacity constraints for high-speed rail networks. In this paper, a bilevel optimization model is formulated and the constraints include track section capacity per unit time, train seat capacity, and the gap between the number of starting trains and that of ending trains at a station. In the upper level, the objective is to minimize train operational cost and passenger travel cost, and the decision variables include the line of each train, carriage composition of each train, train stop patterns, train start times, and train arrival and departure times at stops in the line plan. In the lower level, a schedule-based passenger assignment method, which assigns time-varying demand on trains with seat capacity constraints by simulating the ticket-booking process, is used to evaluate the line plan obtained in the upper level. A simulated annealing algorithm is developed to solve the model in which some strategies are designed to search for neighborhood solutions, including reducing train carriages, deleting trains, adding trains, increasing train carriages, and adjusting train start times. Finally, an application to the Chinese high-speed rail network is presented. The numerical results show that (i) the average time deviations between the expected departure times and the actual boarding times of passengers are within 30 min, (ii) the unserved passengers are less than 200, and (iii) the average load factors of trains are about 70%. Hence, line plan solutions meet time-dependent demand well and satisfy the capacity constraints for high-speed rail networks.
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Yu, Xiaoquan, Wei Li, Shuo Li, Yingze Yang, and Jun Peng. "Cooperative Reference Velocity Regulation Control for Virtual Coupling Systems of Heavy-Haul Trains." Sustainability 15, no. 18 (September 7, 2023): 13425. http://dx.doi.org/10.3390/su151813425.
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Virtual coupling systems are important for improving the safety and efficiency of heavy-haul trains by coordinating the velocities of heavy-haul trains. However, the set point change of reference velocity leads to unsafe train operation. To address this issue, in this paper, a cooperative reference velocity regulation control method is proposed for virtual coupling systems of heavy-haul trains, which can smoothly adjust the train velocity during the operation process. Firstly, the heavy-haul trains are characterized by a cyber-physical model, where the physical layer models the longitudinal dynamics of the trains, while the cyber layer represents the communication topology of the trains using graph theory. Secondly, a cooperative control law is designed to achieve velocity consensus and maintain a safe distance between adjacent trains. The set point modulation method is utilized to smoothly adjust the reference velocity of heavy-haul trains, suppressing velocity fluctuations of heavy-haul trains. The proposed approach is validated through extensive simulations under acceleration and deceleration conditions. Simulation results verify that the proposed method can significantly reduce the velocity fluctuations during the operation of virtual coupling systems when compared with the classical cooperative control method.
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Lee, Samuel CK, Michelle L. Gerdom, and Stuart A. Binder-Macleod. "Effects of Length on the Catchlike Property of Human Quadriceps Femoris Muscle." Physical Therapy 79, no. 8 (August 1, 1999): 738–48. http://dx.doi.org/10.1093/ptj/79.8.738.
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Abstract Background and Purpose. Recent reports have suggested that electrical stimulation trains that take advantage of the catchlike property of skeletal muscle can produce higher forces from skeletal muscle than traditionally used constant-frequency trains. This study investigated the effects of catchlike-inducing trains on human quadriceps femoris muscles while the knee joint was held at 15 degrees of flexion. Subjects and Methods. Subjects (N=12) were tested with constant-frequency trains that had interpulse intervals ranging from 10 to 160 milliseconds and comparable catchlike-inducing trains. Data were collected during the control condition (1 train every 10 seconds) and during repetitive contractions (1 train per second). Results. During control and repetitive activation conditions, catchlike-inducing trains produced approximately 5% to 110% greater peak forces than comparable constant-frequency trains, depending on the frequencies being compared. Total forces produced (ie, force-time integrals) were increased up to 59% and 49% during the control and repetitive activation conditions, respectively. Conclusion and Discussion. These results support earlier findings that catchlike-inducing trains may be advantageous in functional electrical stimulation applications.
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WANG, Dandan, Heng DENG, Jingyuan ZHAN, and Liguo ZHANG. "Online Model Predictive Control for Energy-saving Train Operation in Passenger-Freight Mixed Lines." Promet - Traffic&Transportation 36, no. 6 (December 20, 2024): 1039–53. https://doi.org/10.7307/ptt.v36i6.589.
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This paper focuses on the online energy-saving operation control problem for passenger and freight trains running in a single-track railway line. Firstly, we design a centralised optimisation method to generate energy-saving reference profiles for both passenger and freight trains, in order to improve the punctuality of passenger trains and to reduce the total running time of freight trains in a central way. Secondly, we propose the distributed model predictive control (DMPC) based online trajectory optimisation problems for both types of trains, subject to their respective operational constraints including safety, punctuality, static speed limits and temporary speed restrictions. Then we formulate an online train operation control algorithm based on the centralised optimisation method for the initialisation of train trajectories and the DMPC method for the online trajectory planning. Finally, the proposed algorithm is applied to case studies of passenger and freight trains in a single track railway, and the numerical simulation results show that the proposed algorithm can realise online control for energy-saving train operation in the presence of input disturbances and temporary speed restrictions.
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Song, Zongying, Shuo Li, Xiaoquan Yu, Yingze Yang, and Xingzhong Wang. "Cooperative Active Disturbance Rejection Control for Heavy-Haul Trains." Journal of Advanced Computational Intelligence and Intelligent Informatics 29, no. 1 (January 20, 2025): 165–74. https://doi.org/10.20965/jaciii.2025.p0165.
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Cooperative control of multiple heavy-haul trains can improve the safety and efficiency of heavy-haul railway transportation. However, the influence of internal and external unknown disturbances for multiple heavy-haul trains is a serious obstacle, which will lead to imprecise train operation control. To address this issue, a cooperative active disturbance rejection control for heavy-haul trains is proposed. First, a multi-mass point longitudinal dynamic model of heavy-haul trains is established to meet the actual operation. Second, a cooperative active disturbance rejection controller is designed to estimate and compensate for the disturbance caused by the interaction between the trains and environment. Moreover, the extended state observer is leverage to estimate the nonlinear disturbance online, which enhances the resistance of multiple heavy-haul trains to nonlinear time-varying disturbance and suppresses the overshoots of train velocities and inter-train distance. Finally, the performance of the proposed method is verified in two different simulation scenarios: acceleration and deceleration conditions. The simulation results show that the proposed method reduces the maximum relative displacement by 38.9% and the velocity error by 54.5%.
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Chen, Angyang, Xingchen Zhang, Junhua Chen, and Zhimei Wang. "Joint optimization of high-speed train timetables, speed levels and stop plans for increasing capacity based on a compressed multilayer space-time network." PLOS ONE 17, no. 3 (March 3, 2022): e0264835. http://dx.doi.org/10.1371/journal.pone.0264835.
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With the steady increase in passenger volume of high-speed railways in China, some high-speed railway sections have faced a difficult situation. To provide more transport services, it is necessary to add as many trains as possible in a section to increase capacity. To solve this problem, a compressed multilayer space-time network model is constructed with the maximum number of trains that can be scheduled in the train timetable as the objective. The combination of the train stop plan and speed level is represented by the layer of network where the train is located, and constraints such as train selection, train safety, train overtake and cross-line trains are considered. A method based on timing-cycle iterative optimization is designed to decompose the original problem into multiple subproblems, and the solving order of the subproblems is determined by a heuristic greedy rule. Taking the Beijing-Jinan section of the Beijing-Shanghai high-speed railway as an example, the maximum number of trains was increased by 12.5% compared with the timetable before optimization. The saturated timetables provide detailed schedules, which helps decision-makers better adjust the timetable to run more trains.
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Szkopiński, Janusz, and Andrzej Kochan. "Maximization of Energy Efficiency by Synchronizing the Speed of Trains on a Moving Block System." Energies 16, no. 4 (February 10, 2023): 1764. http://dx.doi.org/10.3390/en16041764.
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The publication deals with the problem of the effect of interference with the movement of the “preceding” train on the movement of the “following” train in the case of efforts to reduce the distance between trains on a moving block interval. The paper presents results of the simulations for train of the ED250 type for a set of 135 traffic situations: for three contexts of reducing the speed of the “preceding” train, for five variants of the method of controlling the “following” train and for nine initial distances between these trains. The results confirmed the possibility of gaining time and energy benefits by implementing an appropriate method of controlling the “following” train, as well as providing insights into the area of shortening the gaps between trains, including the pursuit of synchronizing the speed of trains and possibly coupling them into a so-called virtual couples.
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Pilipenko, O., D. Kolesnik, A. Berezniak, V. Kohan, and O. Pankul. "MEANS, STANDS AND MACHINES FOR TESTING GEAR WHEELS AND GEAR TRAINS OF HELICOPTER REDUCTION TRAINS." Наукові праці Державного науково-дослідного інституту випробувань і сертифікації озброєння та військової техніки, no. 9 (December 3, 2021): 97–117. http://dx.doi.org/10.37701/dndivsovt.9.2021.13.
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The production and repair of such high-tech and important products as helicopters‟ reduction trains is impossible without comprehensive testing of these products, starting with the manufacture of their individual parts and assemblies and ending with the delivery of reduction trains to the customer.
Various means for testing of gear wheels‟ rims and gear trains of helicopter‟s reduction trains, which have found application in testing equipment, are presented. Devices, testers, stands and machines for various tests are considered in order to control the characteristics of gear trains of aviation reduction trains after certain periods of their operation and repair, aimed at achieving better performance during further operation.
The considered traditional metrological means of control of gear rims, gear measuring machines and complexes, some stands and machines for testing of reduction trains, pulse controllers and roll machines give an idea of various methods and means of control of gear wheels and gear trains of helicopters‟ reduction trains.
The main method of experimental research of gear trains of reducers is stand tests both on movable gear wheels and on roll machines.
Until recently, the most common method for monitoring and diagnosing gear trains has been vibrography, however, existing techniques do not give an accurate picture of the train condition, especially the contact surface of the teeth. During the operation of the gear train as a part of the helicopter‟s reduction train, signals from other sources (rotors, blades, shafts, bearings) are superimposed on the vibration signal generated by the gear train which significantly complicates the extraction and processing of the desired vibration signal.
One of the most effective methods for monitoring and diagnosing the technical condition of kinematic chains of different complexity, which includes gear trains of helicopters„ reducers is kinematometry. The disadvantage of traditional kinematometry is the need to use high-precision sensors for the frequency and phase of the rotor rotation.
Control of vibration from the early 1990s to the present time is the most advanced control, the means and methods of which are well developed in the aviation industry.
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Zhen, Hui, Lin Min Jia, and Guo Qiang Cai. "A Positioning System For Subway Trains Based on RFID." Applied Mechanics and Materials 610 (August 2014): 808–13. http://dx.doi.org/10.4028/www.scientific.net/amm.610.808.
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Subway train positioning technology is one of the key technologies, however when red band appears in dispatch center, train ground communication fails and other issues, you need a back-up emergency systems to provide train position information for the station dispatchers in order to arrange train route. This paper describes a back-up system for positioning subway trains. The system is a combination of vehicle and ground subway train assisted positioning system, it can fast and accurate get the location information of subway trains, to provide protection of safe and efficient operation for the subway trains.
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Fufacheva, M. V. "The laws of distribution of some parameters when organizing the movement of trains." Herald of the Ural State University of Railway Transport, no. 3 (2021): 27–39. http://dx.doi.org/10.20291/2079-0392-2021-3-27-39.
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The article discusses the key factors for the organization of train traffic. The analysis of statistical parameters of the intervals of departure of freight trains from railway stations and the length of the freight train flow is carried out. Based on these train schedules, graphical dependences of the intervals of departure of trains from separate points on the volume of train traffic and the distribution of train lengths in even and odd directions are constructed. Polynomial dependencies with coefficients of variation are derived. The curve of the second-order Erlang distribution function for the departure intervals is constructed. It is determined that the average departure intensity in one hour is equal to three trains, and the average departure interval lies between the 25th and 35th minutes with a probability of 0.793. There is a correlation between the coefficient of variation (mean square deviation) of the departure interval and its average daily deviation. The power function of the analytical ratio of the coefficient of variation from the average interval of departure of freight trains from the technical stations of the Krasnoyarsk railway during the day is determined using the least squares method. The degrees of correspondence of theoretical and statistical distributions of the number of cars in trains are studied using the Kolmogorov criterion with the calculation of the probability value and confirmation that the distribution of the number of cars in trains obeys the binomial law. Using the Pearson agreement criterion, it is proved that the frequency of departure of freight trains from railway stations obeys the exponential distribution law.
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Guan, Chengyu, Zemin Zhou, and Xinwu Zeng. "Optimal Waveform Design Using Frequency-Modulated Pulse Trains for Active Sonar." Sensors 19, no. 19 (September 30, 2019): 4262. http://dx.doi.org/10.3390/s19194262.
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Frequency-modulated pulse trains can be applied in active sonar systems to improve the performance of conventional transmitted waveforms. Recently, two pulse trains have been widely researched as the transmitted waveforms for active sonars. The LFM-Costas pulse train was formed by modulating the linear frequency-modulated (LFM) waveform via the Costas sequence to remove the Doppler ambiguity of LFM pulses. The generalized sinusoidal frequency-modulated (GSFM) waveform, another frequency-modulated pulse train, achieved an ideal ambiguity function shape with thumbtack mainlobe. In this paper, we focus on constructing an optimization model to optimize the LFM-Costas and GSFM pulse trains with the genetic algorithm. The pulse trains can be improved on properties of both ambiguity function and correlations between sub-pulses. The optimized pulse trains are proven to have better detection performance than those of the initial pulse trains, including the lower sidelobe levels of ambiguity function, as well as lower cross-correlation property. Moreover, it is affirmed that the reverberation suppression performance of pulse trains has also been improved through the optimization model.
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Krylov, V. V. "Spectra of Low-Frequency Ground Vibrations Generated by High-Speed Trains on Layered Ground." Journal of Low Frequency Noise, Vibration and Active Control 16, no. 4 (December 1997): 257–70. http://dx.doi.org/10.1177/026309239701600404.
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Increase in speeds of modern railway trains is usually accompanied by higher levels of generated ground vibrations. In the author's earlier paper [V.V. Krylov, Applied Acoustics, 44, 149–164 (1995)], it has been shown that especially large increase in vibration level may occur if train speeds v exceed the velocity of Rayleigh surface waves in the ground cR., i.e., v > cR. Such a situation might arise, for example, with French TGV trains for which speeds over 515 km/h have been achieved. The present paper investigates the effect of geological layered structure of the ground on ground vibrations generated by high-speed trains. It is shown that, since Rayleigh wave velocities in layered ground are dispersive and normally increase at lower frequencies associated with deeper penetration of surface wave energy into the ground, the trans-Rayleigh condition v > cR may not hold at very low frequencies. This will cause a noticeable reduction in low-frequency components of generated ground vibration spectra. Theoretical results are illustrated by numerically calculated frequency spectra of ground vibrations generated by single axle loads travelling at different speeds and by TGV or Eurostar high-speed trains.
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Chen, Yuhui, Hongzhe Zhao, Menghan He, and Yanling Pan. "Scientific calculation and application of safety marking principles." Theoretical and Natural Science 34, no. 1 (April 29, 2024): 214–21. http://dx.doi.org/10.54254/2753-8818/34/20241187.
Full textAbstract:
In today's era, trains have become an indispensable mode of transportation for people, yet safety hazards are inevitable during the process of trains entering stations. To study these safety hazards and the principles behind the design of safety markings, we combine the Bernoulli Effect and the conservation of mechanical energy in fluids, taking into account factors such as a person's weight, volume, and distance from the train. We derive an expression that relates the pressure experienced by individuals to the train's speed, the train's cross-sectional area, the distance between the individual and the train, and the area of the individual subjected to force. By comparing this with the general friction force that corresponds to real-life situations, we find that the distances for safety markings provided by the national "Railway Technical Management Regulations" for high-speed train and dynamic train stations are reasonable: for speeds not exceeding 120km/h, the distance is 1000mm; for speeds over 120km/h but not exceeding 160km/h, the distance is 1500mm; and for speeds over 160km/h up to 200km/h, the distance is 2000mm, regardless of the platform height. Based on the factors affecting the safety markings on railway platforms, four practical safety recommendations are proposed.
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Lee, Jeonghee. "A Train’s Dilemma in Two Trains Running." Journal of Humanities and Social sciences 21 10, no. 1 (February 28, 2019): 175–84. http://dx.doi.org/10.22143/hss21.10.1.13.
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Lin, H.-T., and S.-H. Ju. "Three-dimensional analyses of two high-speed trains crossing on a bridge." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 217, no. 2 (March 1, 2003): 99–110. http://dx.doi.org/10.1243/095440903765762841.
Full textAbstract:
This paper investigates the dynamic characteristics of the three-dimensional vehicle-bridge system when two high-speed trains are crossing on a bridge. Multispan bridges with slender piers and simply supported beams were used in the dynamic finite element analysis. A response ratio (RR) was defined in this study to represent the ratio of the vehicle-bridge interaction of two-way trains to that of a one-way train. The finite element results indicate that this ratio increases significantly when two-way trains run near the same speed, and the maximum value is approximately equal to or smaller than two for the vertical dynamic response. This means that the maximum dynamic response of the two-way trains is at most twice that of the one-way train. When the two-way train speeds are sufficiently different, the response ratio approaches one on average, which means that the dynamic effect of the two-way train is similar to that of the one-way train. Finite element results also indicate that the averaged response ratio in the three global directions is about 1.65 when the two-way trains run at the same speed.