Generation of the transport service offer with application to timetable planning considering constraints due to maintenance work

Line planning is an important step in strategic timetable planning in public transport. In this step the transport offer for the customer is generated by the public transport operator, whereby the resulting costs for the operator should be as deep as possible. Mathematical models for line planning allow to create optimized line plans quickly. Planners can use these models to rate and select different alternatives. This is particularly valuable under the aspect of increasing maintenance and construction tasks of the railway infrastructure. We show, that in this case, it is possible to create functional requirements for automated timetable creation from the result of line planning step. The practical use of the involved models is illustrated by a real application example

Kundenfreundliche und robuste Ersatzfahrpläne während Bau- und Unterhaltsintervallen

An der ZHAW wurde ein Verfahren entwickelt, um in kürzester Zeit Ersatzfahrpläne für Bau- und Unterhaltsintervalle zu erstellen – ein für den stabilen Bahnbetrieb zunehmend wichtiges Thema. Die Methode berücksichtigt nicht nur betriebliche Aspekte wie die temporären Einschränkungen der Bahnanlage, sondern stellt gleichzeitig auch den Kundennutzen ins Zentrum der Planung. Dadurch kann das beste Transportangebot in Bezug auf Reisezeiten und Zuverlässigkeit realisiert werden

Generation of interactive questionnaires using YAWL-based workflow models

A concept is introduced in this article which has strong practical impact for computer aided system configuration. System configuration is a cumbersome and fault sensitive task while setting up systems in a broad range of business applications like ERP (enterprise resource planning) and other workflow-systems. Given a generic process or workflow model in YAWL-notation (yet another workflow language) or any other process modeling language like business process model and notation or WFMC (workflow management coalition), it could be stated that, by using a set of reduction rules as introduced, it is possible to generate a hierarchically structured tree of sub graphs of the workflow graph-representation. According to the notation used, authors call these sub graphs facts. The tree structure of the graph-representation on one hand and the logical relation between the branches and leafs of the tree on the other can be utilized to create a set of constraints and dependencies among the single facts. Some researchers showed that the nested branches can be associated to (predefined) questions with respect to the configuration of a workflow management system, for instance an ERP-application. They presented an algorithm which dynamically sorts the questions and answers in a maximum efficient configuration path, while working through the corresponding questionnaire. By combining the different elements as facts, constraints on questions, and configuration space, it is thus possible to algorithmically generate the efficient structured and interactive questionnaire for the configuration of workflow systems and algorithmically check the consistency (dead lock free, free of synchronization structural conflict) of the underlying workflow model. The concept was tested in the prototype of the interactive questionnaire for configuration of the web-service based ERP-Application Posity

Rapid development of ICT business services by business engineers independent of computer scientists

Current software development requires computer scientists to create and to adapt services to new or changing needs. In addition development and maintenance of software is time and cost intensive. Customizing of standard software is laborious. Software engineering research approaches as Domain Engineering, Model Driven Software Engineering and Product Line Engineering try to increase the abstraction level of the specification of the models to reduce the required time and money to build applications and services but they still demand the implementation by computer scientists. In two projects supported by the CTI (Commission for Technology and Innovation of the Swiss Confederation) we analysed how to achieve a higher level of abstraction and how to specify database-centric business services in a manner business engineers are able to create and to adapt services completely by themselves. Besides the methodology to specify these services (data structure, business rules, etc.), methods and technologies to hide all technical aspects (infrastructure, software architecture, versioning etc.) entirely from the business engineer had to be developed. In this paper an according graphical notation to specify services or complete applications is discussed

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

The OpenTrack API : case study using opentrack for benchmarking automatically generated timetable scenarios specified by the transport service intention

Presentation of a case study using OpenTrack for benchmarking automatically generated timetable scenarios specified by the transport service intention

Mehr Kapazität dank innovativem Bahnbetrieb

Ein Team aus Ingenieuren und Forschern arbeitet an einer technischen Lösung zur genauen Überwachung und Steuerung des Zugverkehrs. Die Auswirkungen von Verspätungen oder Ausfällen könnten damit besser aufgefangen und die Auslastung des Schienennetzes generell optimiert werden

Dynamic rescheduling based on predefined track slots

For any Railway Network, increased operational performance (or reliability) is a paramount, and in terms of cost, the most effective way to find extra capacity. The PULS 90 program of the Swiss Federal Railways intends to use modern communications technology to incorporate individual train driver’s performance into the traffic control loop. In order to achieve this, the fast and comprehensive delivery of on-line “scheduling information” into each train’s driving cab will be required. However, first, the mathematical challenges of achieving almost instantaneous, dynamic slot rescheduling on a large scale must be resolved. The approach taken by the SBB infrastructure division has been to segment the network according to traffic characteristics and to then develop and deploy algorithmic approaches capable of calculating new schedules on demand

A multi-component closed-loop control framework for rail traffic networks

The operation of rail transport systems has become an increasingly challenging task over the last decades. One of the main reasons is the conflict between the surge in passenger and freight demand and the capacity constraints of the railway system (on railway lines and at railway stations). To allow for a better understanding of the system dynamics in different operational states (including disruptions) and to have improved control strategies at hand, a multi-component simulation framework, representing an entire closed-loop operation environment for railway networks is currently under way. Based on this framework, railway network operators shall be enabled to investigate timetable and scenario generation, railway traffic operations, operational decision support, and operational performance criteria. In addition, the architecture of the framework shall allow for investigating the effects of moving from a distributed, event driven train control system (where involved operational parties are only weakly interacting) towards an increasingly integrated, time controlled and automated operational concept. This concept of tight time control requires all operational processes to be continuously monitored with respect to the production schedule. Deviations exceeding some pre-determined tolerance thresholds will results in a re-adjustment of the production plan in real-time. A dedicated rescheduling algorithm will be implemented to achieve this goal. This algorithm is based on a resource-constrained multi-commodity flow model for conflict-free train scheduling recently developed at ETH Zurich. To explicitly take into account the various parties (agents) involved, the system can be configured such that the agents behave according to existing or virtual profiles. For instance, train drivers might be technically enabled to follow new operational targets like re-adjusted train speeds while approaching conflict points. With this framework, scenarios for different operational and technical conditions as well as for internal and/or external disturbances can be investigated and the differences in performance with respect to customer satisfaction can be evaluated (represented for example by the overall train delay, cumulated passenger delays or timely availability of customer information). The framework, called Rail Transport Service Environment (RTSE), consists of three main modules: (i) a traffic simulation environment, (ii) a system state monitoring module, and (iii) the rescheduling algorithm mentioned above. The modules are interconnected through standard communication interfaces so that each module can be exchanged easily depending on the user environment. Railway traffic simulations are carried out using the dedicated railway simulation tool OpenTrack. The tool is used by various train operation and train infrastructure companies in order to test, amongst others, the feasibility of timetables or signalling scenarios. The simulated traffic scenarios will be interpreted by an automated monitoring module (including some threshold detection mechanism, where the thresholds depend on the operational policies, etc.), which compares actual and planned process states and induces rescheduling actions executed by the rescheduling algorithm, if required. Those rescheduling actions result in new (adjusted) state space plans, which take into account changes in process states and the eventually reduced availability of resources