36 research outputs found
Optimal Reinsertion of Cancelled Train Lines
One recovery strategy in case of a major disruption in a rail network is to cancel all trains on a specific line of the network. When the disturbance has ended, the cancelled line must be reinserted as soon as possible. In this article we present a mixed integer programming (MIP) model for calculating the best way to reinsert cancelled train lines in a rail network covered by a periodic timetable. Using a high abstraction level it has been possible to incorporate the temporal aspect in the model only relying on the information embedded in the train identification numbers of each departure. The model finds the optimal solution in an average of 0.5 CPU seconds in each test case
The Rolling Stock Recovery Problem
DSB S-tog (S-tog) operates on the double tracked, suburban network surrounding Copenhagen, Denmark. S-tog is the sole operator on the network. The network is owned and controlled by the infrastructure manager BaneDanmark.
During the last years there has been an increased focus on developing tools to aid the planning process in railway transportation. The tools are computer software, which can fully or partly automate some part of the planning process. As in other industries the initial focus has been on strategic, tactical and operational planning. Only lately focus has turned to the area of short term and real time planning. This paper concentrates on the area of rolling stock real time planning.
In practice rolling stock dispatchers monitor the operation of the rolling stock plan and the depot plans. When the rolling stock plan is disrupted, the rolling stock dispatcher makes real time decisions on the re-assignments of train units to train tasks. This process is called recovery. An automated tool will improve the recovery process, help supplying sufficient seat capacity for passengers and reduce the operating cost
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.
Robustness and Recovery in Train Scheduling - a simulation study from DSB S-tog a/s
This paper presents a simulation model to study the robustness of
timetables of DSB S-tog a/s, the city rail of Copenhagen. Dealing with
rush hour scenarios only, the simulation model
investigates the effects of disturbances
on the S-tog network. Several timetables are analyzed with respect
to robustness. Some of these are used in operation and some are generated
for the purpose of investigating timetables with specific alternative
characteristics
Disruption Management in Passenger Railway Transportation
This paper deals with disruption management in passenger
railway transportation. In the disruption management process, many
actors belonging to different organizations play a role. In this paper
we therefore describe the process itself and the roles of the
different actors.
Furthermore, we discuss the three main subproblems in railway
disruption management: timetable adjustment, and rolling stock and
crew re-scheduling. Next to a general description of these problems,
we give an overview of the existing literature and we present some
details of the specific situations at DSB S-tog and NS. These are
the 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 Operations
Research models for disruption management in the railway context,
models and techniques that have been developed for related problems
in the airline world are discussed as well.
Finally, we address the integration of the re-scheduling processes
of the timetable, and the resources rolling stock and crew
Genome Sequence of the Lager Brewing Yeast, an Interspecies Hybrid
This work presents the genome sequencing of the lager brewing yeast (Saccharomyces pastorianus) Weihenstephan 34/70, a strain widely used in lager beer brewing. The 25 Mb genome comprises two nuclear sub-genomes originating from Saccharomyces cerevisiae and Saccharomyces bayanus and one circular mitochondrial genome originating from S. bayanus. Thirty-six different types of chromosomes were found including eight chromosomes with translocations between the two sub-genomes, whose breakpoints are within the orthologous open reading frames. Several gene loci responsible for typical lager brewing yeast characteristics such as maltotriose uptake and sulfite production have been increased in number by chromosomal rearrangements. Despite an overall high degree of conservation of the synteny with S. cerevisiae and S. bayanus, the syntenies were not well conserved in the sub-telomeric regions that contain lager brewing yeast characteristic and specific genes. Deletion of larger chromosomal regions, a massive unilateral decrease of the ribosomal DNA cluster and bilateral truncations of over 60 genes reflect a post-hybridization evolution process. Truncations and deletions of less efficient maltose and maltotriose uptake genes may indicate the result of adaptation to brewing. The genome sequence of this interspecies hybrid yeast provides a new tool for better understanding of lager brewing yeast behavior in industrial beer production