ATMOS 2005 Abstracts Collection -- Selected Papers from the 5th Workshop on Algorithmic Methods and Models for Optimization of Railways

This issue contains six papers that were presented in preliminary form at the 5th Workshop on Algorithmic Methods and Models for Optimization of Railways (ATMOS 2005), held at Palma de Mallorca, Spain, October 7, 2005 in conjunction with ALGO 2005. These papers are representative of several areas of research within the scope of ATMOS: rolling stock circulation and engine assignment, station location, line planning, railway traffic scheduling and dispatching, transfer optimization within network design, and fast traffic information systems

04261 Abstracts Collection -- Algorithmic Methods for Railway Optimization

From 20.06.04 to 25.06.04, the Dagstuhl Seminar 04261 ``Algorithmic Methods for Railway Optimization\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Railway timetabling from an operations research

In this paper we describe Operations Research (OR) models and techniques that can be used for determining (cyclic) railway timetables. We discuss the two aspects of railway timetabling: ($i$) the determination of arrival and departure times of the trains at the stations and other relevant locations such as junctions and bridges, and ($ii$) the assignment of each train to an appropriate platform and corresponding inbound and outbound routes in every station. Moreover, we discuss robustness aspects of both subproblems

Integer Constraints for Train Series Connections

The scheduling of train services is subject to a number of constraints describing railway infrastructure, required train services and reasonable time-intervals for waiting and transits. Timetable planners at Dutch Railways are nowadays supported by a software tool, called CADANS, which produces a feasible timetable on an hourly basis. In this paper, connection requirements between train series are written in the format of the CADANS model. It turns out that this leads to nontrivial combinatorial scheduling issues

Rescheduling of Railway Rolling Stock with Dynamic Passenger Flows

Traditional rolling stock rescheduling applications either treat passengers as static objects whose influence on the system is unchanged in a disrupted situation, or they treat passenger behavior as a given input. In case of disruptions however, we may expect the flow of passengers to change significantly. In this paper we present a model for passenger flows during disruptions and we describe an iterative heuristic for optimizing the rolling stock to the disrupted passenger flows. The model is tested on realistic problem instances of NS, the major operator of passeng

Routing trains through a railway station based on a Node Packing model

In this paper we describe the problem of routing trains through a railway station. This routing problem is a subproblem of the automatic generation of timetables for the Dutch railway system. The problem of routing trains through a railway station is the problem of assigning each of the involved trains to a route through the railway station, given the detailed layout of the railway network within the station and given the arrival and departure times of the trains. When solving this routing problem, several aspects such as capacity, safety, and customer service have to be taken into account. In this paper we describe this routing problem in terms of a Weighted Node Packing Problem. Furthermore, we describe an algorithm for solving this routing problem to optimality. The algorithm is based on preprocessing, valid inequalities, and a branch-and-cut approach. The preprocessing techniques aim at identifying super uous nodes which can be removed from the problem instance. The characteristics of the preprocessing techniques with respect to propagation are investigated. We also present the results of a computational study in which the model, the preprocessing techniques and the algorithm are tested based on data related to the railway stations Arnhem, Hoorn and Utrecht in the Netherlands.mathematical economics and econometrics ;

Shuttle Planning for Link Closures in Urban Public Transport Networks

Urban public transport systems must periodically close certain links for maintenance, which can have significant effects on the service provided to passengers. In practice, the effects of closures are mitigated by replacing the closed links with a simple shuttle service. However, alternative shuttle services could reduce inconvenience at a lower operating cost. This paper proposes a model to select shuttle lines and frequencies under budget constraints. We propose a new formulation that allows a minimal frequency restriction on any line that is operated and minimizes passenger inconvenience cost, which includes transfers and frequency-dependent waiting time costs. This model is applied to a shuttle design problem based on a real-world case study of the Massachusetts Bay Transportation Authority network of Boston, Massachusetts. The results show that additional shuttle routes can reduce passenger delay compared to the standard industry practice, while also distributing delay more equally over passengers, at the same operating budget. The results are robust under different assumptions about passenger route choice behavior. Computational experiments show that the proposed formulation, coupled with a preprocessing step, can be solved faster than prior formulations

Re-scheduling in railways: the rolling stock balancing problem

This paper addresses the Rolling Stock Balancing Problem (RSBP). This problem arises at a passenger railway operator when the rolling stock has to be re-scheduled due to changing circumstances. These problems arise both in the planning process and during operations. The RSBP has as input a timetable and a rolling stock schedule where the allocation of the rolling stock among the stations does not fit to the allocation before and after the planning period. The problem is then to correct these off-balances, leading to a modified schedule that can be implemented in practice. For practical usage of solution approaches for the RSBP, it is important to solve the problem quickly. Therefore, the focus is on heuristic approaches. In this paper, we describe two heuristics and compare them with each other on some (variants of) real-life instances of NS, the main Dutch passenger railway operator. Finally, to get some insight in the quality of the proposed heuristics, we also compare their outcomes with optimal solutions obtained by solving existing rolling stock circulation models

Reinventing Crew Scheduling at Netherlands Railways

In this paper we describe the successful application of a sophisticated Operations Research model and the corresponding solution techniques for scheduling the 6,500+ drivers and conductors of the Dutch railway operator NS Reizigers (Netherlands Railways). In 2001 the drivers and conductors were very dissatisfied with the structure of their duties, which led to nation wide strikes. However, the application of the model described in this paper led to the development of an alternative production model (‘Sharing Sweet & Sour’) that both satisfied the drivers and conductors, and at the same time supported an increment of the punctuality and efficiency of the railway services. The plans produced according to the alternative production model trimmed personnel costs by about $4.8million (or1.2$7 million per year are also achievable