scholarly journals A Timetable Rescheduling Approach and Transition Phases for High-Speed Railway Traffic during Disruptions

2017 ◽  
Vol 2607 (1) ◽  
pp. 82-92 ◽  
Author(s):  
Peijuan Xu ◽  
Francesco Corman ◽  
Qiyuan Peng ◽  
Xiaojie Luan
Keyword(s):  
Real Time ◽  
Traffic Control ◽  
High Speed ◽  
Job Shop ◽  
Mixed Integer ◽  
Mixed Integer Linear Program ◽  
Solution Quality ◽  
High Speed Railway ◽  
Railway Traffic ◽  
Train Speed

Research focused on the real-time rescheduling of high-speed railway traffic with a quasi-moving blocking system and transition process affected by the entrance delays and disruptions determining speed limitation. A mixed-integer linear program model related to a job shop model of operations is formulated to reduce the final delay (tardiness) of trains, where three objective functions combine different manners related to traffic control and speed management. The dynamic interaction between train speed and distance headway is considered in the model. Through experiments on a real-world high-speed line in China, the solution quality of the model is assessed by the delay distribution of trains or the smooth degree of train speed profile. The model manages to optimize traffic in the transition from a disordered condition (when disruptions appear) to a normal condition (after disruptions) for real-time operations. In conclusion, there are two and three transition phases for the cases without and with entrance delays, respectively, seen by analyzing the deviation between the rescheduled and planned timetables.

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.

Formulation of Real-Time Control Policy for Oversaturated Arterials

2000 ◽  
Vol 1727 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Edward B. Lieberman ◽  
Jinil Chang ◽  
Elena Shenk Prassas
Keyword(s):  
Real Time ◽  
Traffic Control ◽  
Storage Capacity ◽  
Control Policy ◽  
Mixed Integer ◽  
System Throughput ◽  
Real Time Control ◽  
Mixed Integer Linear Program ◽  
Real Time Traffic ◽  
Queue Lengths

The formulation of a real-time traffic control policy designed expressly for oversaturated arterials is presented, and the operating protocol is described. Its objectives are to ( a) maximize system throughput, ( b) fully use storage capacity, and ( c) provide equitable service. This control policy, known as RT/IMPOST (real-time/internal metering policy to optimize signal timing), is designed to control queue growth on every saturated approach by suitably metering traffic to maintain stable queues. Consistent with this approach, bounds on queue lengths and signal offsets are determined. A mixed-integer linear program (MILP) tableau is formulated to yield optimal values of signal offsets and queue length for each approach. A nonlinear (quadratic) programming formulation adjusts the arterial green-phase durations of each signal cycle so that the actual arterial queue lengths on each saturated approach will continually closely approximate the optimal queue lengths computed by the MILP formulation. The policy principles are as follows: ( a) the signal phase durations “meter” traffic at intersections servicing oversaturated approaches to control and stabilize queue lengths and to provide equitable service to competing traffic streams; and ( b) the signal coordination (i.e., offsets) controls the interaction between incoming platoons and standing queues in a way that fully uses the available storage capacity, keeps intersections clear of queue spillback, and maximizes throughput.

scholarly journals Integrated Train Rescheduling and Rerouting during Multidisturbances under a Quasi-Moving Block System

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Peijuan Xu ◽  
Dawei Zhang ◽  
Jingwei Guo ◽  
Dan Liu ◽  
Hui Peng
Keyword(s):  
Mathematical Model ◽  
High Speed ◽  
Experimental Tests ◽  
Mixed Integer ◽  
Railway Traffic ◽  
Train Rescheduling ◽  
High Speed Trains ◽  
Np Hard Problem ◽  
Train Speed ◽  
Step Algorithm

It is known that it is critical for train rescheduling problem to address some uncertain disturbances to keep the normal condition of railway traffic. This paper is keen on a mathematical model to reschedule high-speed trains controlled by the quasi-moving blocking signalling system impacted by multidisturbances (i.e., primary delay, speed limitation, and siding line blockage). To be specific, a mixed-integer linear programming is formulated based on an improved alternative graph theory, by the means of rerouting, reordering, retiming, and train control. In order to adjust the train speed and find the best routes for trains, the set of alternative arcs and alternative arrival/departure paths are considered in the constraints, respectively. Due to this complex NP-hard problem, a two-step algorithm with three scheduling rules based on a commercial optimizer is applied to solve the problem efficiently in a real-word case, and the efficiency, validity, and feasibility of this method are demonstrated by a series of experimental tests. Finally, the graphical timetables rescheduled are analysed in terms of free conflicts of the solution. Consequently, the proposed mathematical model enriches the existing theory about train rescheduling, and it can also assist train dispatchers to figure out disturbances efficiently.

The dynamic amplification factors for continuous beam bridges along high-speed railways

2021 ◽  
pp. 136943322110032
Author(s):  
Lin Ma ◽  
Wei Zhang ◽  
Steve C.S. Cai ◽  
Shaofan Li
Keyword(s):  
Fundamental Frequency ◽  
High Speed ◽  
Continuous Beam ◽  
Empirical Formulas ◽  
High Speed Railway ◽  
Amplification Factors ◽  
Girder Bridges ◽  
Continuous Beam Bridge ◽  
Train Speed ◽  
Dynamic Amplification

In this paper, the dynamic amplification factors (DAFs) of high-speed railway continuous girder bridges are studied. The vehicle-bridge interactions (VBIs) of 13 concrete continuous girder bridges with spans ranging from 48 to 130 m are analyzed, the influences of the train speed, the train marshalling and the bridge fundamental frequency on the DAF are investigated, and the DAF design standard for high-speed railway bridges is discussed. The results indicate that for the continuous beam bridge whose fundamental frequency is less than 3.0 Hz, the maximum DAF is no more than 1.15; while for the bridge examples with a fundamental frequency larger than 3.0 Hz, the maximum DAF reaches 1.25 because the resonance occurs at high train speed. The empirical formulas of the DAFs in the Japan Railway Technical Research Institute (JRTRI) code could provide a conservative estimation of the DAFs of high-speed railway continuous bridges.

Improvement and Lock Calculation of Electric Switch Machine of Railway Turnout

2013 ◽  
Vol 409-410 ◽  
pp. 1496-1501 ◽  
Author(s):  
Jing Mang Xu ◽  
Ping Wang ◽  
Hao Xu
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Lateral Stiffness ◽  
High Speed Railway ◽  
Train Speed ◽  
Working Status ◽  
Stress And Deformation ◽  
Railway Turnout

Electric switch machine locks the crossing rail in the working direction and checks the working status of the crossing. With the increase of train speed, the ZD(J)9 electric switch machine cant satisfy the equipment of high speed railway, This paper studied the optimization; in order to study the lock calculation of nose rail after conversion, a dynamic model is established to research the influence of working status of the crossing. It indicates that for the first traction point, the stress and deformation are mainly affected by scant displacement between nose rail and wing rail; for the second traction point, they are affected by the gap between nose rail and spacer; fastener lateral stiffness doesnt influence the stress status, but the lateral fastener stiffness should not be too small.

Research on High Speed Railway Evaluation of the Sustainable Competitive Advantage

2014 ◽  
Vol 505-506 ◽  
pp. 43-48
Author(s):  
Zhong Yang Lv ◽  
Kang Ning Zheng
Keyword(s):  
Competitive Advantage ◽  
High Speed ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Fuzzy Comprehensive Evaluation ◽  
Sustainable Competitive Advantage ◽  
High Speed Railway ◽  
Systematic Analysis ◽  
Railway Traffic ◽  
Positive Externality

In this paper, in order to improve the high speed railway sustainable competitive advantage as the research objective, systematic analysis of the high-speed railway to obtain sustainable competitive advantage evaluation index, including high-speed railway traffic function advantage, competitive advantage, advantage of positive externality, the Delphi method is used to scientific empowerment of these factors, by constructing fuzzy comprehensive evaluation model, the research conclusion is highway and air passenger is higher than that in high speed railway of competitive advantage

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