AS
A. Sheikholeslami
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1
Disturbances in rail networks propagate delays and reduce the reliability and stability of the train schedules. Thus, it is essential to manage the disturbances in rail networks. Railway disruption management includes effective ways to manage the operations in the case of unanticipated deviations from the original schedule. In this study, the temporary blockage of tracks on the rail network is regarded as a disruption. First, the basic scheduling model with the objective of minimizing the total travel time of trains will be provided. Consequently, the re-scheduling model, which is an extension of the basic model, is presented. The original schedule provided by the basic scheduling model will be used as an input for the re-scheduling model. The integrated model employs different recovery actions to better minimize the negative impact of disturbances on the initial schedule. The new plan includes a set of revised departure times, dwell times, and train running times. A heuristic approach was proposed to design the new plan within a reasonable time. To validate the model, the train re-scheduling model is tested for multiple disruption scenarios with different disruption recovery times on the Iranian rail network. The results indicate that the developed mathematical model produced the best recovery solution with respect to time constraint.
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Disturbances in rail networks propagate delays and reduce the reliability and stability of the train schedules. Thus, it is essential to manage the disturbances in rail networks. Railway disruption management includes effective ways to manage the operations in the case of unanticipated deviations from the original schedule. In this study, the temporary blockage of tracks on the rail network is regarded as a disruption. First, the basic scheduling model with the objective of minimizing the total travel time of trains will be provided. Consequently, the re-scheduling model, which is an extension of the basic model, is presented. The original schedule provided by the basic scheduling model will be used as an input for the re-scheduling model. The integrated model employs different recovery actions to better minimize the negative impact of disturbances on the initial schedule. The new plan includes a set of revised departure times, dwell times, and train running times. A heuristic approach was proposed to design the new plan within a reasonable time. To validate the model, the train re-scheduling model is tested for multiple disruption scenarios with different disruption recovery times on the Iranian rail network. The results indicate that the developed mathematical model produced the best recovery solution with respect to time constraint.
Simulation analysis of the effect of doubling and electrification on the reliability of the rail networks
A case study of Tehran-Mashhad railroad
The reliability assessment of the railway services is a complex procedure that is affected by many different factors. A railway system is reliable when the trains arrive at their destination within the allowed delay threshold. The objective of this study is to investigate the effect of the infrastructure doubling and electrification on the reliability of the train schedules. In this study, advanced event-driven stochastic simulation software is developed to determine the reliability of the train movements. The calculation of the average train delay as a benchmark is provided to evaluate performance. We compared average train delay with the acceptable delay to define a new benchmark to determine the reliability of the train movements. We also analyzed the delay cascading effect along the railway line in order to better illustration of a number of correlations between the arrival and departure delays at different stations. The model has been validated through a real-world case study of Iranian railway. Successful validation of the developed simulation system demonstrated that the model provides accurate reliability estimations in both congested and non-congested situations. Furthermore, the experimental results showed that electrification and doubling improve the reliability significantly.
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The reliability assessment of the railway services is a complex procedure that is affected by many different factors. A railway system is reliable when the trains arrive at their destination within the allowed delay threshold. The objective of this study is to investigate the effect of the infrastructure doubling and electrification on the reliability of the train schedules. In this study, advanced event-driven stochastic simulation software is developed to determine the reliability of the train movements. The calculation of the average train delay as a benchmark is provided to evaluate performance. We compared average train delay with the acceptable delay to define a new benchmark to determine the reliability of the train movements. We also analyzed the delay cascading effect along the railway line in order to better illustration of a number of correlations between the arrival and departure delays at different stations. The model has been validated through a real-world case study of Iranian railway. Successful validation of the developed simulation system demonstrated that the model provides accurate reliability estimations in both congested and non-congested situations. Furthermore, the experimental results showed that electrification and doubling improve the reliability significantly.
Delays and disruptions reduce the reliability and stability of the rail operations. Railway traffic rescheduling includes ways to manage the operations during and after the occurrences of such disturbances. In this study, we consider the simultaneous presence of large disruptions (temporary full or partial blockage of tracks) as well as stochastic variation of operations, as a source of disturbance. The occurrence time of blockage and its recovery time are given. We designed a simulation-based optimization model that incorporates dynamic dispatch priority rules with the objective of minimizing the total delay time of trains. We moreover design a variable neighborhood search meta-heuristic scheme for handling traffic under the limited capacity close to the blockage. The new plan includes a set of new departure times; dwell times, train running times. We evaluate the proposed model on a set of disruption scenarios covering a large part of the Iranian rail network. The result indicates that the developed simulation-based optimization approach has substantial advantages in producing practical solution quickly, when compared to commercial optimization software. In addition, the solutions have a lower average and smaller standard deviation than currently accepted solutions, determined by human dispatcher or by standard software packages.
...
Delays and disruptions reduce the reliability and stability of the rail operations. Railway traffic rescheduling includes ways to manage the operations during and after the occurrences of such disturbances. In this study, we consider the simultaneous presence of large disruptions (temporary full or partial blockage of tracks) as well as stochastic variation of operations, as a source of disturbance. The occurrence time of blockage and its recovery time are given. We designed a simulation-based optimization model that incorporates dynamic dispatch priority rules with the objective of minimizing the total delay time of trains. We moreover design a variable neighborhood search meta-heuristic scheme for handling traffic under the limited capacity close to the blockage. The new plan includes a set of new departure times; dwell times, train running times. We evaluate the proposed model on a set of disruption scenarios covering a large part of the Iranian rail network. The result indicates that the developed simulation-based optimization approach has substantial advantages in producing practical solution quickly, when compared to commercial optimization software. In addition, the solutions have a lower average and smaller standard deviation than currently accepted solutions, determined by human dispatcher or by standard software packages.