scholarly journals Integrated Optimization of the Location–Inventory Problem of Maintenance Component Distribution for High-Speed Railway Operations

2020 ◽  
Vol 12 (13) ◽  
pp. 5447
Author(s):  
Dezhi Zhang ◽  
Shuxin Yang ◽  
Shuangyan Li ◽  
Jiajun Fan ◽  
Bin Ji
Keyword(s):  
Distribution System ◽  
High Speed ◽  
Programming Model ◽  
Distribution Network ◽  
Service Level ◽  
Mixed Integer ◽  
High Speed Railway ◽  
Total Cost ◽  
Component Distribution ◽  
Integrated Optimization

Sustainable distribution network design for the maintenance components of electric multiple units (EMUs) is critical to reduce the problem of unreasonable resource allocation and capital occupation of high-speed railway (HSR) operations. Motivated by the above analysis, this study investigates the integrated optimization of the location and inventory of EMU maintenance component distributions. Aiming to improve the sustainable operation for high-speed railway, we proposed a corresponding nonlinear mixed-integer programming model to determine the location of the distribution center (DC) for EMU maintenance component delivery, inventory control strategy, and corresponding service level. The above optimization model is solved by an adaptive improved genetic algorithm. The proposed model and algorithm are applied to a real-world case study on China’s EMU maintenance components. The findings show that a higher service level is not better to achieve the lower total cost in the maintenance component distribution network. The ratios of transportation modes are significant to balance the service level and total cost of the EMU distribution network. Furthermore, the unit out-of-stock cost and the service level both show great impacts on the total costs of the EMU distribution system. Finally, there exists an optimal ratio of different transport modes, which ensures the least total cost of the EMU distribution system.

Integrated Overnight Train Scheduling and Maintenance Planning for High-Speed Railway Lines

2020 ◽  
pp. 036119812096883
Author(s):  
Dian Wang ◽  
Shuguang Zhan ◽  
Qiyuan Peng ◽  
Wentao Zhou
Keyword(s):  
High Speed ◽  
Programming Model ◽  
Mixed Integer ◽  
Maintenance Planning ◽  
High Speed Train ◽  
High Speed Railway ◽  
Train Scheduling ◽  
Railway Line ◽  
High Speed Trains ◽  
Commercial Solver

Overnight high-speed trains are very popular and convenient for passengers in countries with a large territory like China. However, the overnight high-speed train operation inevitably conflicts with the regular evening maintenance. We focus on both overnight high-speed train scheduling and maintenance planning to eliminate the conflict. Because some of the daytime high-speed trains that run early in the morning or late in the evening also interact with overnight high-speed trains and maintenance, we also allow them to be to slightly rescheduled to improve both the quality of the overnight train timetable and the maintenance plan. Our integrated optimization problem is formulated as a mixed integer linear programming model, which can be solved efficiently by the commercial solver CPLEX. Finally, we validate our model on a large real-world case constructed based on the Beijing–Guangzhou high-speed railway line in China.

Notch-based speed trajectory optimisation for high-speed railway automatic train operation

2021 ◽  
pp. 095440972110421
Author(s):  
Minling Feng ◽  
Chaoxian Wu ◽  
Shaofeng Lu ◽  
Yihui Wang
Keyword(s):  
High Speed ◽  
Applied Force ◽  
Mixed Integer ◽  
High Speed Railway ◽  
Train Operation ◽  
Train Speed ◽  
Automatic Train Operation ◽  
The Impact ◽  
Trajectory Optimisation

Automatic train operation (ATO) systems are fast becoming one of the key components of the intelligent high-speed railway (HSR). Designing an effective optimal speed trajectory for ATO is critical to guide the high-speed train (HST) to operate with high service quality in a more energy-efficient way. In many advanced HSR systems, the traction/braking systems would provide multiple notches to satisfy the traction/braking demands. This paper modelled the applied force as a controlled variable based on the selection of notch to realise a notch-based train speed trajectory optimisation model to be solved by mixed integer linear programming (MILP). A notch selection model with flexible vertical relaxation was proposed to allow the traction/braking efforts to change dynamically along with the selected notch by introducing a series of binary variables. Two case studies were proposed in this paper where Case study 1 was conducted to investigate the impact of the dynamic notch selection on train operations, and the optimal result indicates that the applied force can be flexibly adjusted corresponding to different notches following a similar operation sequence determined by optimal train control theory. Moreover, in addition to the maximum traction/braking notches and coasting, medium notches with appropriate vertical relaxation would be applied in accordance with the specific traction/braking demands to make the model feasible. In Case study 2, a comprehensive numerical example with the parameters of CRH380AL HST demonstrates the robustness of the model to deal with the varying speed limit and gradient in a real-world scenario. The notch-based model is able to obtain a more realistic optimal strategy containing dynamic notch selection and speed trajectory with an increase (1.622%) in energy consumption by comparing the results of the proposed model and the non-notch model.

scholarly journals A Mixed Integer Linear Programming Method for Simultaneous Multi-Periodic Train Timetabling and Routing on a High-Speed Rail Network

2020 ◽  
Vol 12 (3) ◽  
pp. 1131
Author(s):  
Wenliang Zhou ◽  
Xiaorong You ◽  
Wenzhuang Fan
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Mixed Integer Linear Programming ◽  
High Speed ◽  
Programming Model ◽  
Mixed Integer ◽  
High Speed Rail ◽  
Train Timetabling ◽  
Train Timetable ◽  
The Impact

To avoid conflicts among trains at stations and provide passengers with a periodic train timetable to improve service level, this paper mainly focuses on the problem of multi-periodic train timetabling and routing by optimizing the routes of trains at stations and their entering time and leaving time on each chosen arrival–departure track at each visited station. Based on the constructed directed graph, including unidirectional and bidirectional tracks at stations and in sections, a mixed integer linear programming model with the goal of minimizing the total travel time of trains is formulated. Then, a strategy is introduced to reduce the number of constraints for improving the solved efficiency of the model. Finally, the performance, stability and practicability of the proposed method, as well as the impact of some main factors on the model are analyzed by numerous instances on both a constructed railway network and Guang-Zhu inter-city railway; they are solved using the commercial solver WebSphere ILOG CPLEX (International Business Machines Corporation, New York, NY, USA). Experimental results show that integrating multi-periodic train timetabling and routing can be conducive to improving the quality of a train timetable. Hence, good economic and social benefits for high-speed rail can be achieved, thus, further contributing to the sustained development of both high-speed railway systems and society.

scholarly journals Simultaneous Optimization of Train Timetabling and Platforming Problems for High-Speed Multiline Railway Network

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Qin Zhang ◽  
Xiaoning Zhu ◽  
Li Wang ◽  
Shuai Wang
Keyword(s):  
High Speed ◽  
Optimization Problems ◽  
Programming Model ◽  
Simultaneous Optimization ◽  
Resource Assignment ◽  
Railway Network ◽  
High Speed Railway ◽  
Train Timetabling ◽  
Train Timetable ◽  
Railway Operation

The optimization problems of train timetabling and platforming are two crucial problems in high-speed railway operation; these problems are typically considered sequentially and independently. With the construction of high-speed railways, an increasing number of interactions between trains on multiple lines have led to resource assignment difficulties at hub stations. To coordinate station resources for multiline train timetables, this study fully considered the resources of track segments, station throat areas, and platforms to design a three-part space-time (TPST) framework from a mesoscopic perspective to generate a train timetable and station track assignment simultaneously. A 0-1 integer programming model is proposed, whose objective is to minimize the total weighted train running costs. The construction of a set of incompatible vertexes and links facilitates the expression of difficult constraints. Finally, example results verify the validity and practicability of our proposed method, which can generate conflict-free train timetables with a station track allocation plan for multiple railway lines at the same time.

scholarly journals Multi-Period Network Design Problem in Regional Hazardous Waste Management Systems

2019 ◽  
Vol 16 (11) ◽  
pp. 2042 ◽  
Author(s):  
Jun Zhao ◽  
Lixiang Huang
Keyword(s):  
Network Design ◽  
Design Problem ◽  
Programming Model ◽  
Planning Horizon ◽  
Network Design Problem ◽  
Mixed Integer ◽  
Hazardous Wastes ◽  
Total Risk ◽  
Total Cost ◽  
Treatment And Disposal

The management of hazardous wastes in regions is required to design a multi-echelon network with multiple facilities including recycling, treatment and disposal centers servicing the transportation, recycling, treatment and disposal procedures of hazardous wastes and waste residues. The multi-period network design problem within is to determine the location of waste facilities and allocation/transportation of wastes/residues in each period during the planning horizon, such that the total cost and total risk in the location and transportation procedures are minimized. With consideration of the life cycle capacity of disposal centers, we formulate the problem as a bi-objective mixed integer linear programming model in which a unified modeling strategy is designed to describe the closing of existing waste facilities and the opening of new waste facilities. By exploiting the characteristics of the proposed model, an augmented ε -constraint algorithm is developed to solve the model and find highly qualified representative non-dominated solutions. Finally, computational results of a realistic case demonstrate that our algorithm can identify obviously distinct and uniformly distributed representative non-dominated solutions within reasonable time, revealing the trade-off between the total cost and total risk objectives efficiently. Meanwhile, the multi-period network design optimization is superior to the single-period optimization in terms of the objective quality.

scholarly journals Service Station Evaluation Problem in Catering Service of High-Speed Railway: A Fuzzy QFD Approach Based on Evidence Theory

2015 ◽  
Vol 2015 ◽  
pp. 1-25 ◽  
Author(s):  
Xin Wu ◽  
Lei Nie ◽  
Meng Xu
Keyword(s):  
Distribution System ◽  
High Speed ◽  
Evidence Theory ◽  
Approximate Reasoning ◽  
Distribution Centers ◽  
High Speed Railway ◽  
Service Station ◽  
Service Stations ◽  
Evaluation Problem ◽  
Fuzzy Quality Function Deployment

Catering Service of High-Speed Railway (CSHR) starts at suppliers, includes distribution centers and service stations in cities, and ends at cabinets in high-speed trains. In Distribution System Design (DSD) Problem for CSHR, it is critical to evaluate the alternatives of service stations, which is termed as Service Station Evaluation Problem in Catering Service of High-speed Railway (SSEP-CSHR). As a preparation work for DSD, SSEP-CSHR needs to be solved without detailed information and being accompanied with uncertainty. Fuzzy Quality Function Deployment (F-QFD) has been given in the literatures to deal with vagueness in Facility Location Evaluation (FLE). However, SSEP-CSHR that includes identifying and evaluating stations requires not only dealing with the vague nature of assessments but also confirming them. Based on evidence theory, this paper introduces the framework to give the truth of proposition “x is A.” Then it is incorporated into a two-phase F-QFD with an approximate reasoning to enable the truth of the decisions to be measured. A case study that refers to 85 alternative stations on Chinese high-speed railway will be carried out to verify the proposed method. Analysis shows that the proposed evaluation method enhances scientific credibility of FLE and allows decision makers to express how much is known.

scholarly journals A Study on the Practical Carrying Capacity of Large High-Speed Railway Stations considering Train Set Utilization

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Bin Guo ◽  
Leishan Zhou ◽  
Yixiang Yue ◽  
Jinjin Tang
Keyword(s):  
Carrying Capacity ◽  
High Speed ◽  
Programming Model ◽  
High Speed Railway ◽  
Railway Stations ◽  
China Studies ◽  
Important Nodes ◽  
Entire Network

Methods for solving the carrying capacity problem for High-Speed Railways (HSRs) have received increasing attention in the literature in the last few years. As important nodes in the High-Speed Railway (HSR) network, large stations are usually the carrying capacity bottlenecks of the entire network due to the presence of multiple connections in different directions and the complexity of train operations at these stations. This paper focuses on solving the station carrying capacity problem and considers train set utilization constraints, which are important influencing factors that have rarely been studied by previous researchers. An integer linear programming model is built, and the CPLEX v12.2 software is used to solve the model. The proposed approach is tested on a real-world case study of the Beijing South Railway Station (BS), which is one of the busiest and most complex stations in China. Studies of the impacts of different train set utilization constraints on the practical station carrying capacity are carried out, and some suggestions are then presented for enhancing the practical carrying capacity. Contrast tests indicate that both the efficiency of the solving process and the quality of the solution show huge breakthroughs compared with the heuristic approach.

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