Timetable Development Research Articles

Multiobjective Timetable Development Tool for Railway Strategic Planning in Norway

Strategic planning is critical in helping railways develop optimal programs for improving their business by making service more attractive and efficient. Preparing a strategic plan requires comparing multiple alternatives and options, each requiring time-consuming planning, evaluation, and analysis. To improve this process Jernbanedirektoratet, Norway’s Railway Directorate, began a research project to develop a state-of-the-art railway timetable generation tool that could be integrated into the agency’s existing timetable-planning process. The new tool, called Automatic Timetabler with Multiple Objectives, is designed to transform conceptual passenger and freight service requirements into working timetables, while ensuring robustness and minimizing time losses. It is designed to bridge the gap between less detailed (macroscopic) models used in timetable development and detailed (microscopic) traffic simulation models. More specifically, it is a mesoscopic model, simplifying some infrastructure elements while using more detailed representations of others (e.g., using specific track allocations in stations). In practice, the tool quickly provides planners with many feasible and good timetables using high-level timetable requirement data. This ability is very useful for strategic planning because it enables planners to quickly evaluate alternative timetable concepts. This paper describes the new timetable generator tool, its development, and the results of a case study application.

Integrated Optimization for Commuting Customized Bus Stop Planning, Routing Design, and Timetable Development With Passenger Spatial-Temporal Accessibility

The customized bus (CB) is an innovative type of transit service that can provide a personalized efficient transit services for passengers and environmental friendliness and congestion alleviation in metropolitan areas. This work develops an integrated optimization method for CB stop deployment, route design, and timetable development optimization problems while meeting travel demands as much as possible to obtain system-optimal CB service plans. Through the perspective of space-time network, the CB service design problem (CBSDP) is formulated as an integrated optimization model with the objectives of maximizing passenger accessibility and minimizing operating cost. An inconvenience index of passengers is introduced in the problem to measure the service quality, and the total number of stops for all involved CB routes is set as one of the objectives to optimize the total cost of the CB system. A heuristic approach is applied to generate efficient solutions for the CBSDP. Two types of instance, namely, a numerical experiment and a real-world instance, are implemented to demonstrate the performance of the proposed method. We also conduct a series of sensitive analyses to explore the influences of various parameters on the CB system for capturing the interaction among stops, routes, and timetables. Final results show that the CB plans obtained by the proposed method can provide efficient services by balancing passenger convenience and operating cost.

Maintenance timetable planning based on mesoscopic infrastructure and the transport service intention

Planners of maintenance intervals and operations have a strong need for rapid development and assessment of comprehensive and reliable timetable scenarios, which are able to satisfy the requirements of both, the train operating company and the infrastructure operating company. To address these requirements, in this paper we present a use case that is based on the ‘track-choice and line-rotation’ extension of ‘PESP’, the commonly known model for the generation of periodic event schedules. We call the extended model ‘TCFPESP’. This model takes into account the event flexibility requirement of the ‘service intention’ and makes use of a mesoscopic track infrastructure representation. Both properties support an iterative timetable development process with a ‘progressive feasibility assessment’, a feature that is requested in practice.The ‘service intention’ represents the functional timetable specification. The specification is given by an integrated line concept consisting of a set of lines with data defining their types, frequencies, stop sequence, rotation times and connections. Our proposed model takes functional and operational timetable specifications as input and is applied in an iterative way by changing technical parameters in order to generate a timetable with a feasible capacity allocation.Both, the service intention as well as the mesoscopic infrastructure representation can be configured in the line planning and timetabling system Viriato. This system is widely used by public transport planners and operators. It is therefore possible to configure our timetable model by a standard planning tool.After the description of the methods developed, we provide a practical proof of concept by testing the use case for different maintenance scenarios. Thereby we can show that, based on the service intention planners are able to quickly develop feasible timetable scenarios for maintenance intervals. The use case presented in this paper refers to generating short-term timetable scenarios but can also be used in long-term strategic planning.

Simultaneous Optimization of Speed and Buffer Times with an Application to Liner Shipping

Transport companies often have a published timetable. To maintain timetable reliability despite delays, companies include buffer times during timetable development and adjust the traveling speed during timetable execution. We develop an approach that integrates timetable development and execution. We model execution of the timetable as a stochastic dynamic program (SDP). An SDP is a natural framework to model random events causing (additional) delay, propagation of delays, and real-time optimal speed adjustments. However, SDPs alone cannot incorporate the buffer allocation during timetable development, as buffer allocation requires choosing the same action in different states of the SDP. Motivated by the practical need for timetables that operate well during timetable execution, our model seeks the buffer allocation that yields the SDP that has minimal long-run average costs. We derive several analytical insights into the model. We prove that costs are joint convex in the buffer times, and we develop theory to compute subgradients. Our fast and exact algorithm for buffer time allocation is based on these results. Our case study considers container vessels sailing a round tour consisting of 14 ports based on Maersk data. The algorithm finds the optimal timetable in roughly 70 seconds for realistic problem instances. The optimal timetable yields cost reductions of about four to 10 million U.S. dollars per route per year in comparison with the current timetable. Finally, we show the robustness of our solution approach for different parameter settings using a sensitivity analysis. The online appendices are available at https://doi.org/10.1287/trsc.2018.0842 .

Large-Scale Demand Driven Design of a Customized Bus Network: A Methodological Framework and Beijing Case Study

In recent years, an innovative public transportation (PT) mode known as the customized bus (CB) has been proposed and implemented in many cities in China to efficiently and effectively shift private car users to PT to alleviate traffic congestion and traffic-related environmental pollution. The route network design activity plays an important role in the CB operation planning process because it serves as the basis for other operation planning activities, for example, timetable development, vehicle scheduling, and crew scheduling. In this paper, according to the demand characteristics and operational purpose, a methodological framework that includes the elements of large-scale travel demand data processing and analysis, hierarchical clustering-based route origin-destination (OD) region division, route OD region pairing, and a route selection model is proposed for CB network design. Considering the operating cost and social benefits, a route selection model is proposed and a branch-and-bound-based solution method is developed. In addition, a computer-aided program is developed to analyze a real-world Beijing CB route network design problem. The results of the case study demonstrate that the current CB network of Beijing can be significantly improved, thus demonstrating the effectiveness of the proposed methodology.

Variational Genetic Algorithm for NP-hard Scheduling Problem Solution

The article is devoted to the study of metaheuristic method for scheduling problems solution. The article describes genetic algorithm successfully applied to solve the problems. The article considers the model of a problem of an optimal timetable development, describes genetic algorithm applied to the problem. The results of the algorithm are provided.

Optimal timetable development for community shuttle network with metro stations

This paper investigates an issue for optimizing synchronized timetable for community shuttles linked with metro service. Considering a passenger arrival distribution, the problem is formulated to optimize timetables for multiple community shuttle routes, with the objective of minimizing passenger’s schedule delay cost and transfer cost. Two constraints, i.e., vehicle capacity and fleet size, are modeled in this paper. The first constraint is treated as soft, and the latter one is handled by a proposed timetable generating method. Two algorithms are employed to solve the problem, i.e., a genetic algorithm (GA) and a Frank–Wolfe algorithm combined with a heuristic algorithm of shifting departure times (FW-SDT). FW-SDT is an algorithm specially designed for this problem. The simulated and real-life examples confirm the feasibility of the two algorithms, and demonstrate that FW-SDT outperforms GA in both accuracy and effectiveness.

Analysis of a new public-transport-service concept: Customized bus in China

In recent years, an innovative mode of public transport (PT) service, known as customized bus (CB), has been springing up across China. This service, providing advanced, personalized and flexible demand-responsive PT, is offered to specific clientele, especially commuters. The present work analyzes, for the first time, the evolution of this new PT concept across 30 Chinese cities where CB systems are currently in operation or under construction. Unlike conventional bus transit service, CB users are actively involved in various operational planning activities. CB personalizes PT service by using interactive and integrated information platforms, such as internet website, telephone and smartphone. The analysis comprises three components: first, a comprehensive examination of the background of CB and its temporal and spatial distribution in China; second, an analysis of the operation-planning process, including elements of online demand collection, network route design, timetable development, vehicle scheduling, crew scheduling, real-time control, and fare design and collection: third, a summary of the results of the examination and analysis, presenting pros, cons and recommendations. The successful implementation of CB in China demonstrates that this new PT service concept can effectively meet the ever-increasing mobility needs of large populations nation-wide. Similarly, the present work can provide a valuable reference for policymakers, academic researchers, PT practitioners and others worldwide.

An assessment of the impact of demand management strategies for efficient allocation of airport capacity

Airport demand management strategies have the potential to mitigate congestion and delays. However, the extent to which the delays can be reduced using such strategies is not clear. In this paper, we develop a bound on the minimum possible level of delays that can be achieved using these strategies. We solve the aggregated timetable development and fleet assignment problem to minimise the system–wide delays assuming a single monopolistic carrier that satisfies all the passenger demand in the USA and maintains the same level–of–service as achieved with the current revenue management practices of individual carriers. The problem is formulated as a large–scale, integer linear programming model and solved using linear programming relaxation and heuristics. A network delay simulator is used for calculating the delays under different capacity scenarios. The results indicate the large inefficiencies in the usage of airport infrastructure in the domestic US caused by competitive airline scheduling decisions.

Integrated Robust Airline Schedule Development

In air transportation, airline profitability is influenced by the airline's ability to build flight schedules. In order to generate operational schedules, airlines engage in a complex decision-making process, referred to as airline schedule planning. Up to now, the generation of flight schedules has been separated and optimized sequentially. The schedule design has been traditionally decomposed into two sequential steps. The frequency planning and the timetable development. The purpose of the second problem of schedule development, fleet assignment, is to assign available aircraft types to flight legs such that seating capacity on an assigned aircraft matches closely with flight demand and such that costs are minimized. Our work integrates these planning phases into one single model in order to produce more economical solutions and create fewer incompatibilities between the decisions. We propose an integrated robust approach for the schedule development step. We design the timetable ensuring that enough time is available to perform passengers’ flight connections, making the system robust avoiding misconnected passengers. An application of the model for a simplified IBERIA network is shown.

Public-transport vehicle scheduling with multi vehicle type

The public-transport (transit) operation planning process commonly includes four basic activities, usually performed in sequence: (1) network route design, (2) timetable development, (3) vehicle scheduling, and (4) crew scheduling. The purpose of this work is to address the vehicle scheduling problem, while taking into account the association between the characteristics of each trip (urban, peripheral, inter-city, etc.) and the vehicle type required for the particular trip. The problem is based on given sets of trips and vehicle types, where the categories are arranged in decreasing order of vehicle cost. Therefore, each trip can be carried out by its vehicle type, or by other types listed in prior order. This problem can be formulated as a cost-flow network problem with an NP-hard complexity level. Thus, a heuristic algorithm is developed in this work, based on the Deficit Function theory. Two examples are used as an expository device to illustrate the procedures developed, along with a real-life example of a bus company.

A Database Approach to Course Timetabling

This paper discusses computer based support systems for the task of creating timetables in an educational establishment. In particular, we consider the use of a database management system for the ‘book-keeping’ aspects of timetable development. The system described has been implemented at Loughborough University Business School and has proved to be a very effective means of assisting the production of high quality timetables as well as related teaching lists and forms.

A Database Approach to Course Timetabling

This paper discusses computer based support systems for the task of creating timetables in an educational establishment. In particular, we consider the use of a database management system for the ‘book-keeping’ aspects of timetable development. The system described has been implemented at Loughborough University Business School and has proved to be a very effective means of assisting the production of high quality timetables as well as related teaching lists and forms.