Train Diagram Research Articles

Integrated Optimization of Train Diagrams and Rolling Stock Circulation with Full-Length and Short-Turn Routes of Virtual Coupling Trains in Urban Rail Transit

The advancement of virtual coupling technology in urban rail transit has facilitated the online coupling and decoupling of trains, enabling a range of flexible transportation configurations, including various route types and adjustable formations. This study targets the fluctuating passenger demands on urban rail lines, aiming to minimize both passenger travel and operational costs. The model integrates constraints associated with virtual coupling, train operations, rolling stock circulation, and the interaction between virtually coupled trains and passenger arrivals. New decision variables are introduced to depict the train formation state under virtual coupling scenarios. An integrated optimization model for train diagrams and rolling stock circulation under virtual coupling conditions is developed, employing a genetic-simulated annealing algorithm informed by train operation simulations. A case study on an urban rail line during the morning peak examines the optimization of train diagrams for full-length and short-turn routes. Findings confirm that virtual coupling technology effectively adapts to lines with uneven passenger flow distribution, significantly enhancing the match between supply and demand, equalizing spatial and temporal traffic variations, and harmonizing the quality of passenger services with operational efficiency.

Multiobjective optimization of railway cold-chain transportation route based on dynamic train information

Freight train is selected to pick up and hang refrigerated containers according to railway freight train diagram in China. A multiobjective optimization model of railway cold-chain transportation route is established with total, time, and reliability costs as objective functions on the basis of dynamic train information. Different weights of three objective functions are obtained and weighted sum method is used to transform the multiobjective problem into a single-objective problem according to different transport demands of railway cold-chain transportation participants. An example of k short-circuit optimization algorithm based on genetic algorithm (GA) is designed to prove the feasibility and effectiveness of the proposed model. The empirical analysis showed that different transport times can be obtained by adjusting weights of various optimization objectives in the model to meet diverse needs of railway cold-chain transport participants and selecting differentiated shifts and transfer stations on the same route to provide a variety of transportation time limit options. Results of this study can provide guidance to decision makers in choosing railway transportation schemes.

Measuring the resilience of an urban rail transit network: A multi-dimensional evaluation model

Once an urban rail transit (URT) system breaks down or is deliberately damaged, it will cause tremendous pressure on the whole urban transportation system. Hence, its ability to deal with incidents has become an important research field. Existing studies seldom consider the entire cycle of an incident and ignore changes in passenger travel behavior during emergency events. In this paper, resilience is defined as the ability of absorbing, resisting and recovering when the URT network fails. We propose a multi-dimensional evaluation model for measuring the resilience by calculating multiple abilities with consideration of multi-source data including passenger flow, train diagram, passenger travel choice behavior, network topology, etc. Finally, we present a case study based on real-world data from the Beijing Subway network to illustrate the effectiveness and applicability of the proposed model. Through the resilience analysis, we recognize the critical stations, measure emergency recovery ability and provide necessary information support for reducing the risk of URT incidents.

Train Operations Organization in High-Speed Railway Station Considering Variable Configuration

The train operation problem at the railway station is one of the basic scheduling problems for railway companies, and the decomposition and combination of trains in station platform tracks is an important trend in the railway operation, which further increase the complexity of train routing problem in the high-speed railway station. A reasonable train routing plan is critical for ensuring the safety and efficiency of train operations within the stations. Considering the combination and decomposition process of trains at the station, a multi-objective model is constructed, which determines the receiving routes and departure routes of trains at the railway station with the limited infrastructure capacity, given the station yard layouts, train diagram and relevant technical operation time of the station. A solution framework based on the “constraint method” is designed, and software Gurobi is used to solve the problem. The Pareto optimal solution set is obtained. The results show that when making 1.9% concessions to the minimum route cost, the occupancy balance of platform tracks can be improved by 66.2%, which is taken as the comprehensive application scheme. Compared with the feasible scheme, the comprehensive operation scheme reduces the route cost by 1.9% and improves the occupation balance of platform tracks by 15.4%.

Following Consistency of Energy‐Saving Operation for Urban Rail Trains Based on Event Triggering Mechanism

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%.

Rail potential control with train diagram optimization in multitrain DC traction power system

ABSTRACT Currently, abnormally elevated rail potential exists in the DC traction power system, which greatly threatens the safe operation of the line. In order to realize the reflux safety, timetable optimization of multitrain based on improved Seeker Optimization Algorithm (SOA) is proposed to suppress the rail potential of the system. Firstly, the simulation model of the system is built and the calculation process of rail potential is proposed. Secondly, an optimization model based on maximum rail potential is formulated, where the dwell time is the decision variable and is adjusted to change the regenerative power distribution of the system. Finally, the improved SOA is used to handle the optimization model. Compared with the maximum rail potential before optimization, the simulation results demonstrate that the maximum rail potential is reduced by 55.5% with the proposed method, which greatly improves the reflux safety of the multi-train subway system.

Research on High-Speed Railway Freight Train Organization Method considering Different Transportation Product Demands

The sustained and stable growth of China’s market economy promotes the continuous improvement of transportation demand and puts forward higher requirements for transportation products. At present, as a new product, high-speed rail freight has played an important role in cold chain logistics and high-value-added transportation, which is of great significance to effectively reduce the pollution caused by road transportation and further promote the sustainable development of economy and logistics industry. In the previous study, we studied the organization optimization method of high-speed rail freight train operation scheme and the compilation method of high-speed rail freight train diagram based on the overall demand of freight transportation but did not consider the influence of different high-speed rail freight transportation products on the organization scheme. Therefore, in order to ensure the sustainable development of high-speed rail freight business, based on the demand of high-speed freight products (the freight product for short in the following text), this paper focuses on the optimization method of high-speed rail freight train organization scheme considering different demands. A two-stage freight demand analysis method considering customers’ choice intention and actual supply capacity was designed, comprehensively considering the relationship between operation cost and income, and a model based on different products in order to meet the needs of large-scale case solving was established. In addition, a column generation algorithm was designed. The computational results are encouraging and demonstrate the effectiveness of the model and solution method.

The design of the traffic plan of line S1 of Taizhou railway in Zhejiang Province

At present, China is in the period of rapid urbanization construction, and gradually build a set of efficient, new and fast comprehensive urban transportation system. The urban railway construction with the same city commuter and convenient public transport service can effectively extend the urban development space and accelerate the adjustment process of urban planning and layout. According to the current situation of Taizhou’s economic and traffic development, as well as Taizhou’s unique geographical advantages, combined with the relevant research at home and abroad, this paper comprehensively discusses the necessity of building Taizhou City railway line S1. By sorting out the relevant preliminary, short-term and long-term passenger flow forecast data, this paper calculates the maximum section passenger flow in each period of the day, analyzes the characteristics of passenger flow in each period, compiles the full-time driving plan compilation data, and makes corresponding adjustments according to the actual situation, and finally designs the full-time driving plan to meet the passenger flow demand in each period. The second chapter describes the research background, the third chapter analyzes the characteristics of passenger flow, and the fourth chapter designs the driving plan and draws the train diagram.

Moving block principle-based multi-strategy optimal scheduling method for trains in case of segment blockages

During the daily operation of high-speed railways, unexpected events such as geological disasters or equipment failure may lead to railway segment blockages. A long-duration segment blockage usually leads to large-scale train delays, which cause significant inconvenience to passengers.Adjusting train schedules in real time during segment blockages is an important issue for the dispatch and operation of high-speed railways.For a segment blockage of a known time interval, a mixed integer nonlinear programming (MINLP) model for train speed adjustment and train diagram adjustment is constructed.In this model, in addition to the common scheduling strategies involving train cancellation and departure delay, the deceleration strategy is considered. Under the constraints of traffic safety and station capacity, the objective is to minimize the weighted delays of the three strategies.Additionally, the delay time owing to train speed reduction is calculated based on the train kinematic model, and the safe interval of train operation is controlled using the moving block principle.The model established in this paper can be directly simulated using commercial optimization software CPLEX, and the scheduling scheme is guaranteed to be in real time. This paper also discusses the influence of the three adjustment strategies, i.e., train cancellation, departure delay, and deceleration, on the total delay time. Finally, the model is verified using an example of the Beijing-Shanghai high-speed railway. Results show that the model is reasonable and effective. By implementing the model, a reasonable scheduling scheme can be achieved to address practical problems, and the punctuality rate of trains can be improved.

A methodology of estimating derailment occurrence probability during an earthquake considering effects of railway structure and train diagram

A methodology of estimating derailment occurrence probability during an earthquake considering effects of railway structure and train diagram

The results of modeling and evaluating the dynamics of a road train with an active trailer link based on valve-inductor electric machines

The article describes the results of modeling and evaluating the dynamics of a road train with an active trailer link based on valve-inductor electric machines. It gives a general view and an equivalent road train diagram, shows a generalized simulation model of the movement of a two-link road train developed in the Simulink environment for studying motion in various road conditions. We proposed a reference surface model based on the terrain map, blocks were developed for calculating the road tilt angles separately for the tractor and the semitrailer, taking into account the type of coating under each road train wheel at the current time. The visualization of the movement of the road train is shown, the results of modeling and evaluation of the dynamics of the road train with an active trailer link based on valve-induction electric machines for creating control systems for individual drives of the electric motor-wheel of an active semi-trailer and developing a program and methodology of full-scale experimental research representations.

Study on Microscopic Simulation Technology of Operation Process of Unmanned Vehicle Based on Virtual Track

With the continuous development of unmanned driving technology, more and more unmanned vehicles are on the road to start testing, under this circumstance, how to control these unmanned vehicles has become an urgent issue. Based on the basic idea of virtual track and cellular automata model, this paper researches and designs a microscopic simulation system of the operation process of unmanned vehicles. The aim of this paper is to use the idea of strong controllability of railways to control unmanned vehicles in the form of train diagram to ensure their orderly safety on the road. The stability and correctness of the system are verified through case analysis. At the end of the article, the future research direction is prospected.

A Time-Space Network Model Based on a Train Diagram for Predicting and Controlling the Traffic Congestion in a Station Caused by an Emergency

Timely predicting and controlling the traffic congestion in a station caused by an emergency is an important task in railway emergency management. However, traffic forecasting in an emergency is subject to a dynamic service network, with uncertainty surrounding elements such as the capacity of the transport network, schedules, and plans. Accurate traffic forecasting is difficult. This paper proposes a practical time-space network model based on a train diagram for predicting and controlling the traffic congestion in a station caused by an emergency. Based on the train diagram, we constructed a symmetric time-space network for the first time by considering the transition of the railcar state. On this basis, an improved A* algorithm based on the railcar flow route was proposed to generate feasible path sets and a dynamic railcar flow distribution model was built to simulate the railcar flow distribution process in an emergency. In our numerical studies, these output results of our proposed model can be used to control traffic congestion.

An Empirical Study on the Comprehensive Optimization Method of a Train Diagram of the China High Speed Railway Express

The rapid and stable development of China’s economy has driven the increasing demand for express transportation. Based on network operation, China Railway Corporation of High-speed Railway launched high-speed rail products, which have attracted wide attention from all walks of life. With the application of high-speed express trains, the market structure of express transportation in China will change dramatically, from highways as the main mode of transportation to high-speed railway transportation relying on a high-speed railway network, which will effectively reduce the environmental pollution caused by express transportation and further improve the sustainable development of the economy and the logistics industry. At present, the freight Electric Multiple Units (EMU) has been successfully developed and has entered the final test stage. In the last paper, we have introduced the theory and method of the high-speed rail express train operation plan. In addition, a train diagram is an important foundation of railway transportation organization. In order to ensure the sustainable development of high-speed rail express trains after they are put into use, based on the operation plan of high-speed rail express trains, this paper establishes a comprehensive compilation model of a high-speed rail express train diagram, considering train running time, freight flow distribution scheme, and the operation plan of freight multiple units, and an exact solution algorithm based on the Lagrange relaxation algorithm is designed. The computational results are encouraging and demonstrate the effectiveness of the model and solution method.

Optimizing Train-Set Circulation Plan in High-Speed Railway Networks Using Genetic Algorithm

As a sustainable transportation mode, high-speed railway (HSR) has been developing rapidly during the past decade in China. With the formation of dense HSR network, how to improve the utilization efficiency of train-sets (the carrying tools of HSR) has been a new research hotspot. Moreover, the emergence of railway transportation hubs has brought great challenges to the traditional train-sets’ utilization mode. Thus, in this paper, we address the issue of train-sets’ utilization problem with the consideration of railway transportation hubs, which consists of finding an optimal Train-set Circulation Plan (TCP) to complete trip tasks in a given Train Diagram (TD). An integer programming TCP model is established to optimize the train-set utilization scheme, aiming to obtain the one-to-one correspondence relationship among sets of train-sets, trip tasks, and maintenances. A genetic algorithm (GA) is designed to solve the model. A case study based on Nanjing and Shanghai HSR transportation hubs is made to demonstrate the practical significance of the proposed method. The results show that a more efficient TCP can be formulated by introducing train-sets being dispatched among different stations in the same hub.

Empirical Analysis of Traveling Backwards and Passenger Flows Reassignment on a Metro Network with Automatic Fare Collection (AFC) Data and Train Diagram

Metro (subway) systems are becoming overcrowded in some of China’s mega-cities, such as Beijing, Shanghai, and Guangzhou. As many passengers are unable to board trains on an overcrowded metro network during peak periods, some of them are willing to spend more time and energy by traveling backwards in order to secure a seat or even room for standing. Traditional studies on travel behavior analysis and transit assignment models seldom deal with this situation. We propose a methodology including the affinity propagation cluster method with between-within-proportion (BWP) index and an adaptive “0-1” model named the traveling backwards model (TBM) to identify the phenomenon of “traveling backwards” and to reassign passenger flows on a metro network using automatic fare collection (AFC) data and actual train diagrams. As a numerical example, this integrated approach is applied to the Beijing metro system. Our research shows that the affinity propagation cluster method with BWP index and implicit enumeration algorithm for TBM work well. TBM is a good replacement for the existing assignment model and travel behavior analysis, especially for those mega-cities’ networks in peak hours.

Establishment and Analysis of Energy Consumption Model of Heavy-Haul Train on Large Long Slope

AC heavy-haul trains produce a huge amount of regenerative braking energy when they run on long downhill sections. If this energy can be used by uphill trains in the same power supply section, a reduction in coal transportation cost and an improvement in power quality would result. To accurately predict the energy consumption and regenerative braking energy of heavy-haul trains on large long slopes, a single-particle model of train dynamics was used. According to the theory of railway longitudinal section simplification, the energy consumption and the regenerative braking energy model of a single train based on the train attributes, line conditions, and running speed was established. The model was applied and verified on the Shenshuo Railway. The results indicate that the percentage error of the proposed model is generally less than 10%. The model is a convenient and simple research alternative, with strong engineering feasibility. Based on this foundation, a model of train energy consumption was established under different interval lengths by considering the situation of regenerative braking energy in the multi-train operation mode. The model provides a theoretical foundation for future train diagram layout work with the goal of reducing the total train energy consumption.

Integration Optimization of Timetable and EMU Schedule for High Speed Railway

Based on the analysis of the existing optimization model of train diagram and EMU schedule, combined with the theory and method of integration optimization, the integrated optimization model of high-speed train diagram and EMU schedule was constructed in this thesis, of which the objective function is to build the largest number of running lines between its zones. An EMU schedule plan which better satisfied the given traction plan was obtained in this thesis, using GAMS to solve the model. To test the effectiveness of the model as well as the method, the train diagram and EMU schedule scheme of Beijing-Tianjin Intercity Train was optimized and solved. The optimization results showed that for the EMU schedule of the Beijing-Tianjin line, the number of EMU trains could satisfy the actual operation of high-speed railways, while 6 more trains could be operated at the same time. This solution could provide support of high-speed railway train diagram and EMU schedule scheme for the Beijing-Tianjin line.

A practical model for the train-set utilization: The case of Beijing-Tianjin passenger dedicated line in China.

As a sustainable transportation mode, high-speed railway (HSR) has become an efficient way to meet the huge travel demand. However, due to the high acquisition and maintenance cost, it is impossible to build enough infrastructure and purchase enough train-sets. Great efforts are required to improve the transport capability of HSR. The utilization efficiency of train-sets (carrying tools of HSR) is one of the most important factors of the transport capacity of HSR. In order to enhance the utilization efficiency of the train-sets, this paper proposed a train-set circulation optimization model to minimize the total connection time. An innovative two-stage approach which contains segments generation and segments combination was designed to solve this model. In order to verify the feasibility of the proposed approach, an experiment was carried out in the Beijing-Tianjin passenger dedicated line, to fulfill a 174 trips train diagram. The model results showed that compared with the traditional Ant Colony Algorithm (ACA), the utilization efficiency of train-sets can be increased from 43.4% (ACA) to 46.9% (Two-Stage), and 1 train-set can be saved up to fulfill the same transportation tasks. The approach proposed in the study is faster and more stable than the traditional ones, by using which, the HSR staff can draw up the train-sets circulation plan more quickly and the utilization efficiency of the HSR system is also improved.

Effect of double false pulses in calibrated neutron coincidence collar during measuring time-correlated neutrons from PuBe neutron sources

Effect of double false pulses of preamplifiers in neutron coincidence collar was investigated to explain non-parallel shape of calibrated D/S–MPu curves of two commercial neutron coincidence collars, JCC-31 and JCC-13. Two curves, which were constructed from D/S ratio (doubles and singles count rate), and Pu content MPu, of the same set of secondary standard PuBe neutron sources, should be parallel. Non-parallelism rises doubt about usability of the method based on this curve for determination of Pu content in PuBe neutron sources. We have shown in three steps that the problem originates from double false pulses of preamplifiers in JCC-13. First we used a pulse train diagram for analyzing the non-parallel shape, second we used Rossi-Alpha distribution measured by pulse train recorder developed in our institute and finally, we investigated the effect of inserted noise pulses. This implies a new type of QA test option in traditional multiplicity shift registers for excluding presence of double false pulses.