Integrated optimization of train timetables rescheduling and response vehicles on a disrupted metro line

When an unexpected metro disruption occurs, metro managers need to reschedule timetables to avoid trains going into the disruption area, and transport passengers stranded at disruption stations as quickly as possible. This paper proposes a two-stage optimization model to jointly make decisions for two tasks. In the first stage, the timetable rescheduling problem with cancellation and short-turning strategies is formulated as a mixed integer linear programming (MILP). In particular, the instantaneous parameters and variables are used to describe the accumulation of time-varying passenger flow. In the second one, a system-optimal dynamic traffic assignment (SODTA) model is employed to dynamically schedule response vehicles, which is able to capture the dynamic traffic and congestion. Numerical cases of Beijing Metro Line 9 verify the efficiency and effectiveness of our proposed model, and results show that: (1) when occurring a disruption event during peak hours, the impact on the normal timetable is greater, and passengers in the direction with fewer train services are more affected; (2) if passengers stranded at the terminal stations of disruption area are not transported in time, they will rapidly increase at a speed of more than 300 passengers per minute; (3) compared with the fixed shortest path, using the response vehicles reduces the total travel time about 7%. However, it results in increased travel time for some passengers.Comment: 32 pages, 21 figure

Diagnosis and assessment of operations control interventions : framework and applications to a high frequency metro line

Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 178-180).Service control, the task of implementing the timetable in daily operations on a metro line, plays a key role in service delivery, as it determines the quality of the service as provided to passengers. This thesis proposes a framework for the study of rail service control which builds on the integration and analysis of data from multiple sources and on background knowledge about service control. The framework takes into account the decision environment in which service control takes place and acknowledges that the reliability of the system depends on many factors which are endogenous to it, aspects previously not recognized in a comprehensive manner by researchers and practitioners alike. This research makes use of automatically generated operational and passenger data, which are increasingly available and accessible to transit agencies and allow for addressing questions in service control from multiple perspectives. As a result, this study takes a distinctly different approach than previous research, which has mostly focused on individual service control strategies and relied heavily on modeling and on simplifying assumptions about the objectives and constraints of service control on a metro line. The developed framework consists of four main elements. First, the controller's decision environment is integrated and described based on an extended visit of the author to a control center. Second, an algorithm for reconstructing train operations from signaling data and identifying service control interventions is presented. Third, a measure for assessing the impact of the interventions on operations is introduced.(cont.) The fourth and final element is a set of passenger travel time and reliability measures. The framework is applied to the Central line, a high-frequency line of the London Underground where the control center observations were also made. Three common service control strategies are assessed in terms of their impact on operations and on passengers, and the influence of timetable variables on the frequency of service control interventions is investigated. From observations at the control center, it is found that aside from the objective of maintaining adequate levels of service from an operations perspective and minimizing the impact of schedule deviations on passengers, considerations relating to crew and rolling stock management, safety and infrastructure capacity have a major influence on service control decisions. Given the uncertain environment in which service control operates, a strong preference among controllers for manageable and robust solutions is observed. In the analysis of common control strategies, it is found that in the absence of official policies on the response to certain types of problems on the line and in the presence of the multitude of factors mentioned above, service controllers have developed rules of thumb which may not always be optimal from the passengers' perspective. Furthermore, the fundamental tradeoff is highlighted between the availability of spare resources in form of drivers, trains and infrastructure capacity and the need for service control interventions.(cont.) Regarding the influence of timetable variables, it is found that an increase in scheduled service frequency and in running times on an otherwise unchanged line operating close to its capacity caused significant increases in numbers of service control interventions, mostly due to a higher rolling stock requirement and reduced operational flexibility. Recommendations are made with regards to service control policies, the structure of responsibilities among operational staff, the design of the timetable and the design of the operations control system. Although the results provided by the applications are specific to the Central line, they demonstrate how the elements of the framework can be implemented in a practical setting, and many of the conclusions of this thesis are transferable to other metro lines and systems. Finally, future research in passenger behavior and crew management in the presence of service control interventions is proposed.by André Carrel.S.M.in Transportatio

Bus rapid transit

Effective public transit is central to development. For the vast majority of developing city residents, public transit is the only practical means to access employment, education, and public services, especially when such services are beyond the viable distance of walking or cycling. Unfortunately, the current state of public transit services in developing cities often does little to serve the actual mobility needs of the population. Bus services are too often unreliable, inconvenient and dangerous. In response, transport planners and public officials have sometimes turned to extremely costly mass transit alternatives such as rail-based metros. Due to the high costs of rail infrastructure, cities can only construct such systems over a few kilometres in a few limited corridors. The result is a system that does not meet the broader transport needs of the population. Nevertheless, the municipality ends up with a long-term debt that can affect investment in more pressing areas such as health, education, water, and sanitation. However, there is an alternative between poor public transit service and high municipal debt. Bus Rapid Transit (BRT) can provide high-quality, metro-like transit service at a fraction of the cost of other options. This document provides municipal officials, non-governmental organizations, consultants, and others with an introduction to the concept of BRT as well as a step-by-step process for successfully planning a BRT system

Evaluating the robustness of crew schedules for rail transit systems

Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 145-146).Crew scheduling has traditionally been the last step in the process of service planning, and it has traditionally aimed at minimizing manpower costs because it was assumed that the crew schedule does not directly impact service quality. There has been a growing recognition that crew schedules do in fact affect performance, especially during disruptions, and in that context different crew schedules perform differently. The primary objective of this research is to evaluate the robustness of a crew schedule, or in other words, the performance of a crew schedule under a range of commonly observed disrupted conditions. While the thesis focuses on the Piccadilly Line on the London Underground, the concepts and methods developed are intended to be applicable to a range of metro lines and systems. The thesis has four components: first, a description of the types of incidents that take place on a line, the type of service control interventions used to respond to incidents, and the intimate relationship between the crew schedule and service control policies; second, a comparative analysis of the structure of two Piccadilly Line crew schedules to demonstrate how two crew schedules with similar underlying timetables can have very different structures, and how those structural differences can affect performance; third, the development of a simulation-based framework for evaluating the robustness of crew schedules, and a simulation model of the Piccadilly Line; and finally, the application of the simulation model to evaluate and compare the performance of the same two Piccadilly Line crew schedules under a range of disrupted conditions. Based on observation and understanding the relationship between the crew schedule and service control, a service control module has been implemented in the simulation. This module mimics the actions of a service controller when the operations plan is disrupted and is a key contribution of this research. This allows for the simulation of incidents on the line which leads to an understanding of how the structure of a crew schedule affects its performance during disruptions. Elements of a crew schedule such as slack time and relief locations are identified as key drivers of robustness. The effect of these elements on performance is demonstrated by comparing the simulated performance of two crew schedules that differ in the distribution of these elements. The simulation also allows the testing of hypothetical crew schedules, such as those corresponding to different labour agreements. Therefore, it can be used to test the performance impact of changes in labour agreements. This is demonstrated for the case of the Piccadilly Line through the simulation of two hypothetical scenarios where two different labour constraints are relaxed. The thesis concludes with recommendations to Piccadilly Line and London Underground management and staff regarding crew scheduling, service control and data collection. Results suggest that the slack time in Piccadilly Line crew schedules could be redistributed in a way that improves performance by relaxing other constraints, and that service controllers currently make control decisions without easy access to critical crew information and control decisions could be improved by providing them with better information on crew activities.by Harshavardhan Ravichandran.S.M.in Transportatio

Train planning in a fragmented railway: a British perspective

Train Planning (also known as railway scheduling) is an area of substantial importance to the success of any railway. Through train planning, railway managers aim to meet the needs of customers whilst using as low a level of resources (infrastructure, rolling stock and staff) as possible. Efficient and effective train planning is essential to get the best possible performance out of a railway network. The author of this thesis aims, firstly, to analyse the processes which are used to develop train plans and the extent to which they meet the objectives that they might be expected to meet and, secondly, to investigate selected new and innovative software approaches that might make a material difference to the effectiveness and/or efficiency of train planning processes. These aims are delivered using a range of primarily qualitative research methods, including literature reviews, interviews, participant observation and case studies, to understand these processes and software. Conclusions regarding train planning processes include how the complexity of these processes hinders their effectiveness, the negative impact of the privatisation of British Rail on these processes and the conflicting nature of objectives for train planning in the privatised railway. Train planning software is found not to adequately support train planners in meeting the objectives they are set. The potential for timetable generation using heuristics and for timetable performance simulation to improve the effectiveness of train planning are discussed and recommendations made for further research and development to address the limitations of the software currently available

A framework for evaluating operations control on a metro line: integrating multiple perspectives and automatically collected train and passenger movement data

Transit operations control, the task of implementing the operations plan in daily operations on a metro line, plays a key role in service delivery because it determines the quality of the service experienced by passengers. Yet, it is one of the most poorly understood aspects of rail transit operations. Faced with a disruption or infeasibility, dispatchers typically choose between several response strategies. However, to date, it has been very difficult to evaluate the positive and negative effects of individual control strategies with respect to operations and passenger travel times under real-world conditions. This paper proposes a framework for the study of rail operations control decisions that integrates automatically collected service and passenger demand data, which are increasingly available and accessible to transit agencies. The framework supports a multiperspective analysis methodology that can inform operational policies and plans, and help operations control decision-makers choose the most appropriate strategies to manage service. By using automatically collected data, taking into consideration the operations control decision environment, and acknowledging that the reliability of the resulting service depends on many factors endogenous to it, this paper takes a distinctly different approach from previous studies, which have relied heavily on modeling, assumed simple operating contexts, and did not consider the full range of available data. Two real-world applications of the framework, where control decisions are evaluated in terms of their operational and passenger impacts, are presented. The methodology is found to be versatile and valuable in providing insights that could not have been gained otherwise. Although the framework is applied to the London Underground, its logic, structure, and procedures are applicable and transferable to other metro systems recognizing that certain specifics would need to be tailored to the available data.Transport for London (Organization