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Capacity for express trains on mixed traffic lines
KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. (KTH Railway Group)ORCID iD: 0000-0002-3687-7758
KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. (KTH Railway Group)ORCID iD: 0000-0003-2023-0164
KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.ORCID iD: 0000-0002-2447-2438
2014 (English)In: International Journal of Rail Transportation, ISSN 2324-8386, Vol. 2, no 1, 17-27 p.Article in journal (Refereed) Published
Abstract [en]

Mixed traffic with large speed differences between fast and slower trains consumesmore capacity and makes the system sensitive to disruptions. This article focuses onadequate train configuration for increasing the top speed for express trains like theGreen Train and how that affects capacity on lines with heterogeneous traffic.Microscopic simulation of a future timetable selected by criteria revealed by analyticaltimetable analysis for a chosen structure of services combines the advantages of twomethods and makes it possible to reveal relevant characteristics for different alternatives.Punctual short stops through better train layout and skip-stop operation forregional trains are a few of the measures that are shown to have compensating effectsfor the increase in capacity utilisation and can reduce disruptions. Although it ispossible to reduce the perturbations by means of different measures, the basic problemwith mixing fast and slower trains on the same line still remains.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2014. Vol. 2, no 1, 17-27 p.
Keyword [en]
Green Train, freight train, mixed traffic, train timetabling, punctuality, capacity
National Category
Transport Systems and Logistics
Research subject
Järnvägsgruppen - Gröna tåget
Identifiers
URN: urn:nbn:se:kth:diva-165404DOI: 10.1080/23248378.2013.878292OAI: oai:DiVA.org:kth-165404DiVA: diva2:808254
Projects
Gröna Tåget
Note

QC 20150430

Available from: 2015-04-27 Created: 2015-04-27 Last updated: 2016-12-05Bibliographically approved
In thesis
1. Simulation of rail traffic: Methods for timetable construction,delay modeling and infrastructure evaluation
Open this publication in new window or tab >>Simulation of rail traffic: Methods for timetable construction,delay modeling and infrastructure evaluation
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis covers applications and proposes methods for using simulation in a more effectiveway and also in a wider context than normally used. One of the proposed methods deals withdelay modeling that can be used in a calibration process. Furthermore, a method is presentedthat facilitates the management of having timetables, infrastructure scenarios and delays asvariables in simulation studies. The simulation software used in this thesis is RailSys, whichuses a microscopic formulation to describe the infrastructure and train movements.Timetable changes with respect to allowances and buffer times are applied on a real case(Western Main Line) in Sweden in order to analyze how the on-time performance is affectedfor high-speed passenger trains. The potential benefit is that increased allowances and buffertimes will decrease the probability of train interactions and events where the scheduled trainsequence is changed. The on-time performance improves when allowances are increasedand when buffer times concerning high-speed trains are adjusted to at least five minutes inlocations with potential conflicts. One drawback with this approach is that it can consumemore space in a timetable at certain locations, hence other trains may need adjustments inorder reach these buffer times.Setting up simulations, especially in large networks, can take significant amount of timeand effort. One of the reasons is that different types of delay distributions, representingprimary events, are required in order to obtain conformity with reality if a real timetable andnetwork is modeled. Considering train registration data in Sweden, the separation in primaryand secondary delays is not straightforward. The presented method uses the basic trainregistration data to compile distributions of run time deviations for different train groups ina network. The results from the Southern Main Line case study show that a reasonable goodfit was obtained, both for means and standard deviations of delays. A method for capturingthe variance in freight train operations is proposed, partly based on the findings from theaforementioned study. Instead of modeling early freight trains on time, the true initiationdistributions are applied on time-shifted freight trains.In addition to the already mentioned methods, which are applied on real networks, a methodfor reducing the uncertainties coming from assumptions of future conditions is proposed. It isbased on creating combinatorial departure times for train groups and locations and formulatingthe input as nominal timetables to RailSys. The dispatching algorithm implementedin the software can then be utilized to provide feasible, conflict-managed, timetables whichcan be evaluated. This can be followed by operational simulations with stochastic delays ona subset of the provided timetables. These can then consequently be evaluated with respectto mean delays, on-time performance etc.To facility the use of the infrastructure as a variable in these type of studies, an infrastructuregenerator is developed which makes it relatively easy to design different station layouts andproduce complete node-link structures and other necessary definitions. The number, locationand type of stations as well as the linking of stations through single-track or multi-tracksections can be done for multiple infrastructure scenarios. Although the infrastructure canbe defined manually in RailSys, a considerably amount of time and effort may be needed.In order to examine the feasibility of this method, case studies are performed on fictive linesconsisting mostly of single-track sections. This shows that the method is useful, especiallywhen multiple scenarios are studied and the assumptions on timetables consist of departureintervals for train groups and their stop patterns.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2015. viii, 88 p.
Series
TRITA-TSC-PHD, 15:001
National Category
Transport Systems and Logistics
Research subject
Järnvägsgruppen - Kapacitet; Transport Science
Identifiers
urn:nbn:se:kth:diva-168032 (URN)978-91-87353-64-2 (ISBN)
Public defence
2015-06-09, F2, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20150526

Available from: 2015-05-26 Created: 2015-05-25 Last updated: 2015-05-26Bibliographically approved
2. Timetable evaluation with focus on quality for travellers
Open this publication in new window or tab >>Timetable evaluation with focus on quality for travellers
2016 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Punctuality and reliability are important for travellers. Railway lines with heterogeneous and dense traffic have proved to be prone to generate delays. Faster services and increased traffic have to be counterbalanced with measures for increased reliability. Efficient timetable planning can improve the use of such lines. Usually, that aim is treated from either a capacity or a socio-economic point of view. Because both are important, this thesis aims to combine the fields. A new method to evaluate timetable alternatives is developed. Commonly used methods are combined in a novel way to reveal values for different variables as input for evaluation of alternatives. That enables the comparison of timetable strategies using relevant input data. The idea is to estimate the benefits of a timetable for a traveller by expressing them as a timetable performance index (TTPI). For this purpose, quality indicators and methods to reveal them are identified. In the next step, traditional valuations for relationships between the indicators are used to test different model configurations for evaluation of alternatives, for example alternative departures on the same line or different timetables. 

To treat this multidisciplinary task, several case studies were performed on the Swedish Southern and Western Main lines. As part of a study focussing on methods to measure and evaluate capacity based on travellers’ valuations, the importance of delays was analysed in a questionnaire study and relationships between several variables describing the timetable were found. The other case studies aimed to identify relevant variables and use them to evaluate alternatives. Static and dynamic variables are distinguished. The static ones describe the timetable before operation, the dynamic ones the result of operation or estimated outcome revealed by means of, for example, simulation. Empirical delay data is used in one study, simulation with the microscopic tool RailSys in the others. In one of the studies, analysis is combined with the macroscopic timetabling tool TVEM (Lindfeldt, 2010). The case studies showed the characteristics of the analysed lines described by the chosen variables and which methods and variables are relevant to use for a comparison of timetable slots or evaluation of effects of changes in the timetable. An evaluation method was developed where simulation and timetable analysis reveal the variables. The idea is to construct an analytical function using traditional weights for relationships between the variables to convert the values of the variables into a performance index (PI). Based on a PI for each train slot (TSPI), the TTPI for the whole timetable is estimated. It describes the quality of a timetable in terms of timetable time, i.e. the resulting value is a time that is comparable to the scheduled travel time of one train departure, but includes additional information. With this method, complex timetables can be evaluated regarding their robustness to perturbations, which is valuable for socio-economic analysis of effects of measures applied on the railway system.

As shown in a one of the case studies, quality in terms of punctuality and reliability is important for travellers, at the same time as the design of the timetable has significant impact on these aspects. Timetable analysis and simulation are relevant methods to reveal variables that describe these characteristics and evaluation with the presented method is recommended. The configuration of the TTPI is essential for the outcome whereas it is important to choose variables and parameters adequately. If this is taken into account, the approach can be an efficient way to adjust timetables and choose the best alternative, for instance if a train path or timetable change is to be chosen among several.

Abstract [sv]

Punktlighet och tillförlitlighet är viktiga för resenärer. Järnvägar med heterogen och tät trafik har visat sig vara benägna att generera förseningar. Snabbare tåg och utökat trafikutbud måste uppvägas mot punktlighetsåtgärder. Effektiv tidtabellsplanering kan förbättra utnyttjandet av sådana linjer. Detta ändamål behandlas oftast utifrån antingen kapacitets eller samhällsekonomisk synvinkel. Eftersom bägge är viktiga syftar den här avhandlingen på att kombinera dessa områden. En metod för utvärdering av tidtabellsalternativ utvecklas. Befintliga metoder kombineras på ett nytt sätt för att ta fram värden för olika variabler som indata för en utvärdering av alternativen. Detta möjliggör en jämförelse av tidtabellsstrategier med relevant indata. Idén bygger på att bedöma en tidtabells nytta för resenären genom att uttrycka denna som ett prestationsindex (TTPI). För detta syfte identifieras kvalitetsindikatorer och metoder för att ta fram dessa. Traditionella valideringar för relationerna mellan indikatorerna används sedan för att testa olika konfigurationer av modellen för att utvärdera alternativ, till exempel alternativa avgångar på samma linje eller olika tidtabeller.

För denna multidisciplinära uppgift har flera fallstudier på svenska Södra och Västra stambanan genomförts. Som del av en studie med fokus på metoder för att mäta och utvärdera kapacitet baserad på resenärers värderingar har förseningens värde analyserats med hjälp av en enkätundersökning och relationer mellan några variabler som beskriver tidtabellen hittats. De övriga fallstudierna syftade på att ta fram relevanta variabler och att använda dem för att utvärdera alternativ. Variablerna delades upp i statiska och dynamiska. De statiska beskriver tidtabellen innan den körs, de dynamiska det verkliga utfallet eller det estimerade resultatet framtaget med hjälp av exempelvis simulering. Empiriska försenings­data används i en studie, simulering med det mikroskopiska programmet RailSys i de andra. I en av studierna kombineras analysen med det makroskopiska tidtabellsverktyget TVEM (Lindfeldt, 2010). Fall­studierna visade de analyserade linjernas egenskaper beskrivna av de valda variablerna och vilka metoder och variabler som är relevanta för en jämförelse av olika tåglägen eller en utvärdering hur en ändring i tidtabellen påverkar. En utvärderingsmetod där simulering och tidtabellsanalys används för att ta fram variablerna utvecklades. Idén är att skapa en analytisk funktion med hjälp av traditionella vikter som beskriver sambanden mellan variablerna för att räkna om variablernas värden till en prestations­index (PI). Baserad på en PI för varje tågläge (TSPI) estimeras värdet för hela tidtabellen (TTPI). Detta index beskriver tidtabellens kvalitet som tidtabellstid, dvs. värdet är en tid som är jämförbar med den tidtabellslagda restiden för en avgång, men med ytterligare information inkluderat. Med hjälp av denna metod kan komplexa tidtabeller utvärderas med avseende på robusthet mot störningar vilket är värdefullt för samhällsekonomiska bedömningar av åtgärder i järnvägssystemet.

Som en av fallstudierna visade är kvalitet i form av punktlighet och tillförlitlighet viktig för resenärer samtidigt som tidtabellens utformning har en signifikant påverkan på samma aspekter. Tidtabellsanalys och simulering är relevanta metoder för att ta fram variabler som beskriver dessa egenskaper och utvärdering med de visade metoderna rekommenderades. Modellens konfiguration är betydelsefull för resultatet vilket gör det viktigt att välja variabler och parametrar som är lämpliga. Om detta respekteras kan metoden vara effektiv för att anpassa tidtabeller och välja det bästa alternativet, till exempel när det gäller att välja mellan olika tåglägen eller justeringar i tidtabellen.

Abstract [de]

Pünktlichkeit und Zuverlässigkeit sind wichtig für Reisende. Stark belastete Eisenbahnlinien mit heterogenem Verkehr sind störungsanfällig. Zugleich besteht oft ein Bedarf an schnelleren und häufigeren Verbindungen, was jedoch mit potentiellen negativen Effekten auf die Kapazität aufgewogen werden muss. Effiziente Fahrplan­konstruktion kann die Nutzung solcher Linien verbessern. Dieses Ziel wird meist entweder aus der Sicht der Kapazitätsanalyse oder wirtschaftlichen Aspekten be­trachtet. Da beide Betrachtungsweisen wichtig sind, strebt diese Arbeit die Kombination beider Felder an. Eine Methode für die Auswertung verschiedener Fahrpläne wird entwickelt. Bewährte Methoden werden in neuer Weise kombiniert um Werte für verschiedene Variablen als Input für die Auswertung von Alternativen zu erhalten. Das ermöglicht es potentielle Änderungen im Fahrplan mithilfe relevanter Werte zu vergleichen. Die Idee basiert auf einem Leistungsindex (TTPI), der den Nutzen eines Fahrplans für die Reisenden ausdrücken soll. Zu diesem Zweck werden Qualitätsindikatoren gewählt und Methoden zur Berechnung und Bearbeitung der Indikatoren entwickelt. Traditionelle Werte für die Abhängigkeiten zwischen den Indikatoren dienen dann dem Test verschiedener Modelkonfigurationen sowie der Aus­wertung von Alternativen, z. B unterschiedlicher Trassen oder Fahrpläne.

Für diese multidisziplinäre Aufgabe wurden mehrere Fallstudien für die südliche und westliche Hauptstrecke in Schweden durchgeführt. In einer Fragenbogenstudie mit den Schwerpunkten Mess- und Auswertungsmethoden wurde der Wert von Verspätungen für Reisende untersucht und Verhältnisse zwischen mehreren Indikatoren ermittelt. Die weiteren Fallstudien strebten das Finden relevanter Variablen und deren Anwendung zur Auswertung von Alternativen an. Statische und dyna­mische Variablen wurden unterschieden. Die statischen beschreiben den geplanten Fahrplan vor dem Betrieb, die dynamischen den wirklichen Ausfall oder das beispielsweise durch Simulation berechnete erwartete Resultat. In einer der Fall­studien wurde empirisches Datenmaterial für die Verspätungsdaten genutzt, in den weiteren das mikroskopische Simulationsprogramm RailSys. In einer der Studien wurde die Analyse mit dem makroskopischen Fahrplanungsprogramm TVEM (Lindfeldt, 2010) kombiniert. Die Eigenschaften der untersuchten Linien wurden mithilfe der gewählten Indikatoren analysiert. Weiterhin wurde die Relevanz verschiedener Methoden und Variablen für den Vergleich von Fahrten oder der Beurteilung von Änderungen in Fahrplänen beschrieben. Die gewählte Bewertungs­methode kombiniert Simulation und Fahrplananalyse um die benötigten Werte zu bestimmen. Mithilfe einer analytischen Funktion sollen die Variablen durch An­wen­den von traditionellen Werten für die Zusammenhänge in einen Leistungsindex (PI) umgewandelt werden. Basierend auf einem PI für jede geplante Fahrplantrasse (TSPI) kann der Wert für den gesamten Fahrplan (TTPI) bestimmt werden. Dieser Index übersetzt die Qualität des Fahrplans in Fahrtzeit, das heißt resultiert in einer Zeit, die mit der fahrplanmäßigen Fahrtzeit für eine Fahrt vergleichbar ist, aber zusätzliche Information enthält. Diese Methode ermöglicht es, komplexe Fahrpläne bezüglich Robustheit gegen Störungen auszuwerten, was wertvoll für die Berechnung der Wirtschaftlichkeit von Maßnahmen im Bahnnetz ist.

Wie eine der Fallstudien gezeigt hat, ist die Qualität in Form von Pünktlichkeit und Zuverlässigkeit wichtig für die Reisenden. Gleichzeitig beeinflusst die Ausformung des Fahrplans diese Eigenschaften deutlich. Fahrplananalyse und Simulation sind geeignete Methoden um die Werte der Variablen, die diese Eigenschaften beschreiben, zu bestimmen. Auswertung auf diese Weise wird empfohlen. Die Konfiguration des Models beeinflusst das Ergebnis, weshalb es wichtig ist geeignete Variablen und Parameter zu benutzen. Wird das berücksichtigt, kann die entwickelte Methode effizient für das Verbessern von Fahrplänen angewandt werden und die Wahl der besten Alternative unterstützen, z.B. bei geplanten Änderungen im Fahrplan oder der Wahl zwischen unterschiedlichen Trassen.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2016. 102 p.
Series
TRITA-TSC-LIC, ISSN 1653-445X ; 16-001
Keyword
Capacity evaluation, railway simulation, economic assessment, delays, timetable analysis
National Category
Transport Systems and Logistics
Research subject
Transport Science
Identifiers
urn:nbn:se:kth:diva-190943 (URN)978-91-87353-93-2 (ISBN)
External cooperation:
Presentation
2016-09-23, Nash/Wardrop, Teknikringen 10, 10044 Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20160902

Available from: 2016-09-02 Created: 2016-08-18 Last updated: 2016-09-02Bibliographically approved

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Citation style
  • apa
  • ieee
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  • Other locale
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  • asciidoc
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