Operations research in passenger railway transportation

In this paper, we give an overview of state-of-the-art OperationsResearch models and techniques used in passenger railwaytransportation. For each planning phase (strategic, tactical andoperational), we describe the planning problems arising there anddiscuss some models and algorithms to solve them. We do not onlyconsider classical, well-known topics such as timetabling, rollingstock scheduling and crew scheduling, but we also discuss somerecently developed topics as shunting and reliability oftimetables.Finally, we focus on several practical aspects for each of theseproblems at the largest Dutch railway operator, NS Reizigers.passenger railway transportation;operation research;planning problems

Reliability and heterogeneity of railway services

Reliability is one of the key factors in transportation, both for passengers and for cargo. This paper examines reliability in public railway systems. Reliability of railway services is a complex matter, since there are many causes for disruptions and at least as many causes for delays to spread around in space and time. One way to increase the reliability is to reduce the propagation of delays due to the interdependencies between trains. In this paper we attempt to decrease these interdependencies by reducing the running time differences per track section, i.e. by creating more homogeneous timetables. Because of the complexity of railway systems, we use network wide simulation for the analysis of the alternative timetables. We report on both theoretical and practical cases. Besides a comparison of different timetables, also general timetabling principles are deduced.heterogeneity;simulation;reliability;transportation;railways

Disruption management in passenger railway transportation.

This paper deals with disruption management in passengerrailway transportation. In the disruption management process, manyactors belonging to different organizations play a role. In this paperwe therefore describe the process itself and the roles of thedifferent actors.Furthermore, we discuss the three main subproblems in railwaydisruption management: timetable adjustment, and rolling stock andcrew re-scheduling. Next to a general description of these problems,we give an overview of the existing literature and we present somedetails of the specific situations at DSB S-tog and NS. These arethe railway operators in the suburban area of Copenhagen, Denmark,and on the main railway lines in the Netherlands, respectively.Since not much research has been carried out yet on OperationsResearch models for disruption management in the railway context,models and techniques that have been developed for related problemsin the airline world are discussed as well.Finally, we address the integration of the re-scheduling processesof the timetable, and the resources rolling stock and crew.

The philosophy and practice of Taktfahrplan: a case-study of the East Coast Main Line.

Executive Summary This Working Paper has three purposes, represented by three Parts: - to explain the principles of the Taktfahrplan approach to railway timetabling; - to summarise the implications of the background research on the structure of the network; and - to describe the exercise of constructing a Taktfahrplan for the East Coast Main Line that formed the case-study of the potential benefits of such a scheme compared with the existing timetable. In Part I the broad principles and objectives are first outlined, and the advantages and disadvantages discussed [§ 1.1,1.2]. A Taktfahrplan is based on standard hours and the careful, network-wide coordination of sewices. It is recognised that ultimately the choice between this and conventional timetabling methods must depend on an evaluation of the loss of present flexibility to adjust to time-specific market demands against the gains from enhanced connectivity and from the fact of regularity. Issues concerning resources and the management of peak periods are also explained. Terminology is then dealt with because words and phrases are being used with imprecise and various meanings [§1.3]. There follows a detailed account of the arithmetic rules through which the ideal relationships between train (and bus) sewices can be attained, together with an explanation of the measures that can be taken to make the best compromises in the face of the characteristics of the real network - or to adjust it over time [§ 1.4]. In Part 2 the research to highlight features of the underlying demand for travel is described. This is not a necessary component of strategic timetable planning, but it is argued that it is desirable in order both to break free from the historical baggage and to seize the business, environmental and social-policy opportunities that a 'clean- sheet' timetable would present [§2.1]. The provisional findings from this work (it was left incomplete for reasons that are explained) are then deployed to form the skeleton of a national network connecting 100 important centres with 158 links. This is followed by an analysis of the very variable standards of the rail timetable on those links and of the road competition and by an account of some first thoughts as to how a full-scale Taktfahrplan might start to be developed on this network [§2.2]. This emphasises the inter-relationships between sewices and the inescapable consequences for pathing trains, once it is accepted that sensible spacing of services and striving for good connectivity are more important than optimising routes on a self-contained basis. It was thought appropriate to include a summary of the findings regarding the low-density end of the current rail system in order to indicate the issues that Taktfahrplan might raise in this respect [§2.3]. The East Coast case-study is presented in Part 3. Some technical matters are explained first, including the key point that the exercise used the Viriato timetabling software employed by the Swiss Federal Railways (and many other systems) to construct Taktfahrpliine [§3.1]. Successive sub-parts then describe groups of services: long-distance [§3.2], services within Scotland [§3.3], services in North East England [§3.4], the trans-Pennine network [§3.5] and some of the Yorkshire services [§3.6]

Development of a prototype for the automated generation of timetable scenarios specified by the transport service intention

Within the next 5 to 10 years, public transport in Switzerland as well as in other European countries will experience major technological and organisational changes. However, changes will also take place on the customer side, resulting in different mobility behaviour and demand patterns. These changes will lead to additional challenges for transport service providers in private as well as public domains. Time to market will be a key success factor and it is unnecessary to mention that due to these factors the speed and flexibility of business processes in freight as well as in passenger transport industry have to be increased significantly. Within the railway value chain (line planning, timetabling and vehicle scheduling etc.) the coordination of the individual planning steps is a key success factor. SBB as the leading service provider in public transport in Switzerland has recognized this challenge and, together with various partners, initiated the strategic project Smart Rail 4.0. The ZHAW and especially the Institute for Data Analysis and Process Design (IDP) of the School of Engineering wants to be part of this transformation process and to contribute with research and educational activities. The IDP research therefore aims for the transformation of academic and scientific know-how to practical applicability. In a first step this concerns directly the current Smart Rail 4.0 TMS-PAS project activities, that concentrate on timetabling issues. The IDP project team considers the integration of the line planning and the timetabling process as crucial for practical applications. To address this in the current research project, we present an application concept that enables the integration of these two major process steps in the transport service value-chain. Although it turns out from our research, that the technical requirements for the integration of the process can be satisfied, rules and conditions for a closer cooperation of the involved business units, the train operating companies and the infrastructure operating company, have to be improved and to be worked out in more detail. In addition to a detailed application concept with use cases for the timetabling process we propose a methodology for computer aided timetable generation based on the central planning object known as ‘service intention’. The service intention can be used to iteratively develop the timetable relying on a ‘progressive feasibility assessment’, a feature that is requested in practice. Our proposed model is based on the ‘track-choice’ and line rotation extension of the commonly known method for the generation of periodic event schedules ‘PESP’. The extension makes use of the track infrastructure representation which is also used in the line planning and timetabling system Viriato. This system that is widely used by public transport planners and operators. With the help of Viriato, it is rather easy to configure the timetabling problem in sufficient detail. On the other side, the level of detail of the considered data is light enough to algorithmically solve practical timetabling problems of realistic sizes. Taking into consideration the technical and operational constraints given by rolling stock, station and track topology data on one hand, and the commercial requirements defined by a given line concept on the other, the method presented generates periodic timetables including train-track assignments. In the first step, the standardized data structure ‘service intention’ represents the line concept consisting of train paths and frequencies. Due to the utilization of infrastructure-based track capacities, we are also able to assess the feasibility of the line concept given. Additionally, the method allows for handling temporary resource restrictions (e.g. caused by construction sites or operational disturbances). In order to assess the performance of the resulting timetable we present a framework for performance measurement that addresses the customer convenience (in terms of start-to-end travel time) as well as operational stability requirements (in terms of delay sensitivity and critical relations)

Capacity Statement for Railways

The subject “Railway capacity” is a combination of the capacity consumption and how the capacity is utilized. The capacity utilization of railways can be divided into 4 core elements: The number of trains, the average speed, the heterogeneity of the operation, and the stability. This article describes how the capacity consumption for railways can be worked out, and analytical measurements of how the capacity is utilized. Furthermore, the article describes how it is possible to state and visualize railway capacity. Having unused railway capacity is not always equal to be able to operate more trains. This is due to network effects in the railway system and due to the fact that more trains results in lower punctuality

Railway Capacity Enhancement with Modern Signalling Systems – A Literature Review

In times of ever stronger awareness of environmental protection and potentiation of a beneficial modal split, the railway sector with efficient asset utilization and proper investment planning has the highest chance of meeting customer expectations and attracting new users more effectively. Continuous increase in railway demand leads to an increase in the utilization of railway infrastructure, and the inevitable lack of capacity, a burning problem that many national railways are continually facing. To address it more effectively, this paper reviews available methodologies for railway capacity determination and techniques for its enhancement in the recent scientific literature. Particular focus is given to the possibility of increasing railway capacity through signalling systems and installing the European Train Control System (ETCS). The most important relationships with segments of existing research have been identified, and in line with this, the directions for a potential continuation of research are suggested

Improvement of maintenance timetable stability based on iteratively assigning event flexibility in FPESP

In the operational management of railway networks, an important requirement is the fast adaptation of timetable scenarios, in which operational disruptions or time windows with temporary unavailability of infrastructure, for instance during maintenance time windows, are taken into consideration. In those situations, easy and fast reconfiguration and recalculation of timetable data is of central importance. This local and temporal rescheduling results in shifted departure and arrival times and sometimes even in modified stop patterns at intermediate stations of train runs. In order to generate reliable timetabling results it is a prerequisite that train-track assignments, as well as operational and commercial dependencies are taken into consideration. In order to refer to the right level of detail for modelling track infrastructure and train dynamics in the computer aided planning process we present a generic model that we call Track-Choice FPESP (TCFPESP), as it implements suitable extensions of the established PESP-model. We show, how the service intention (the data structure for timetable specification) together with resource capacity information entered into a standard timetabling tool like Viriato can be utilized in order to configure the TCFPESP model. In addition, we are able to calculate quantitative performance measures for assessing timetable quality aspects. In order to achieve this we present a method for evaluating travel times based on passenger routings and a method for evaluating timetable robustness based on max-plus algebra. This approach supports the planner to generate integrated periodic timetable solutions in iterative development cycles and taking into account intervals for local maintenance work