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Simulation of rail traffic: Methods for timetable construction,delay modeling and infrastructure evaluation
KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.ORCID iD: 0000-0003-2023-0164
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: urn:nbn:se:kth:diva-168032ISBN: 978-91-87353-64-2 (print)OAI: oai:DiVA.org:kth-168032DiVA: diva2:814029
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
List of papers
1. Simulation of modified timetables for high speed trains Stockholm-Göteborg
Open this publication in new window or tab >>Simulation of modified timetables for high speed trains Stockholm-Göteborg
2010 (English)In: Road and Rail Infrastructure / [ed] Stjepan Lakušić, University of Zagreb , 2010Conference paper, Published paper (Refereed)
Abstract [en]

In this research project, involving KTH, Swedish Rail Administration and train operatingcompany SJ, timetable simulation is used on different areas in the Swedish railnetwork. The objective is to develop methods and strategies which can be usefulfor both long and short term timetable planning in the future.This study presents some of the result from simulations done on the Western mainin Sweden. Traffic is mixed with significant differences in average speeds. Thismakes the high speed passenger trains (X2000) sensitive for small delays and disturbancescaused by other, much slower trains.Simulation software RailSys was used to evaluate how increased and decreasedtime supplements for high speed trains affect punctuality. Also buffer times were increasedbetween X2000 and other trains. Delay distributions from previous projectswere implemented in order to model entry delays together with dwell and run timeextensions.Results show that increased buffer times can have a significant effect on punctuality.Some of the studied trains have a situation with dense traffic and high occurrenceof overtakings. This clearly increases average delays and contributes to a lowerpunctuality.

Place, publisher, year, edition, pages
University of Zagreb, 2010
Keyword
train traffic, timetable, simulation
National Category
Transport Systems and Logistics
Research subject
Transport Science
Identifiers
urn:nbn:se:kth:diva-76888 (URN)978-953-6272-38-9 (ISBN)
Conference
CETRA 2010 - First International Conference on Road and Rail Infrastructure. Opatija, Croatia. 17–18 May 2010
Note

TSC import 1068 2012-02-06. QC 20120425

Available from: 2012-02-06 Created: 2012-02-06 Last updated: 2015-07-16Bibliographically approved
2. Calibration of Simulation Model on the Southern Main Line in Sweden
Open this publication in new window or tab >>Calibration of Simulation Model on the Southern Main Line in Sweden
2011 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Suitable analysis methods are needed for evaluation of future timetable scenarios, both in short term operational planning and for strategic planning with a longer time horizon. One method is to use simulation software which makes it possible to model large networks. The Swedish Transport Administration (Trafikverket) is in a process where the aim is to start using simulation software RailSys as a tool for timetable planning. This will at first be applied for long term strategic planning with the possibility to also use it in operational planning further on.

The main focus in this paper is to estimate primary run time extensions from registered data. Ideally these should only represent primary causes, e.g. decreased vehicle performance, variation in driver behaviour or infrastructure malfunctions. These extensions are important in order to make simulations more realistic.

Different reduction levels of registered data are tested in order to estimate primary run time extensions. Registered data used are absolute values without distinction between primary and secondary causes. Calibration simulations are done on the Southern main line in Sweden where the mix of high and low speed trains is substantial.

Keyword
railway operation, simulation, train delay
National Category
Transport Systems and Logistics
Research subject
Järnvägsgruppen - Kapacitet
Identifiers
urn:nbn:se:kth:diva-76754 (URN)
Conference
Railway Engineering 2011. London, UK. 28th June 2011 - 30th June 2011
Note

TSC import 863 2012-02-06. QC 20120413

Available from: 2012-02-06 Created: 2012-02-06 Last updated: 2015-07-16Bibliographically approved
3. Simulation of freight train operations with departures ahead of schedule
Open this publication in new window or tab >>Simulation of freight train operations with departures ahead of schedule
2014 (English)In: Comprail 2012, WIT Press, 2014Conference paper, Published paper (Refereed)
Abstract [en]

Many lines in Sweden have mixed traffic, with both passenger and freight trains. In contrast to passenger trains, freight trains can deviate significantly from their timetable. This study evaluates the effect of modelling freight trains running ahead as well as behind schedule. In previous Swedish studies freight trains have been modelled as being on time or delayed. RailSys is used to simulate a section of the Southern Main Line and a fictive double-track line. Simulation results are compared to data from real train operation. Results show that freight trains can be modelled in a more realistic way. This can improve simulation analysis of freight operations.

Place, publisher, year, edition, pages
WIT Press, 2014
National Category
Transport Systems and Logistics
Research subject
Järnvägsgruppen - Kapacitet
Identifiers
urn:nbn:se:kth:diva-116025 (URN)978-1-84564-581-6 (ISBN)
Conference
13th International Conference on Design and Operation in Railway Engineering11, 13 September 2012, New Forest, UK
Note

TSC import 2156 2013-01-15. QC 20130118

Available from: 2013-01-15 Created: 2013-01-15 Last updated: 2015-09-02Bibliographically approved
4. Capacity for express trains on mixed traffic lines
Open this publication in new window or tab >>Capacity for express trains on mixed traffic lines
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
Keyword
Green Train, freight train, mixed traffic, train timetabling, punctuality, capacity
National Category
Transport Systems and Logistics
Research subject
Järnvägsgruppen - Gröna tåget
Identifiers
urn:nbn:se:kth:diva-165404 (URN)10.1080/23248378.2013.878292 (DOI)
Projects
Gröna Tåget
Note

QC 20150430

Available from: 2015-04-27 Created: 2015-04-27 Last updated: 2016-12-05Bibliographically approved
5. Evaluation of single track timetables using simulation
Open this publication in new window or tab >>Evaluation of single track timetables using simulation
2014 (English)In: IEEE/ASME 2014 Joint Rail Conference, ASME Press, 2014Conference paper, Published paper (Refereed)
Abstract [en]

One way to model train operations and make predictions offuture outcome is to use simulation. Many lines and networksconnecting major cities have a high capacity utilization, meaningthat running additional trains leads to an even more strainedsituation and delays are likely to increase. The mix of averagetrain speeds is also related to capacity and delay propagation.Considering one line or several lines connected in a networka requested train traffic can consist of different train categoriesand departure frequencies. There are usually several possibletimetables satisfying this traffic demand. The infrastructure oftenimplies limitations on the type and volume of traffic that can behandled. Additionally constraints introduced by requests for regularintervals, minimum headways, passenger transfers betweentrains etc. can reduce the number of acceptable timetables.This paper presents an approach using combinatorial traininitiations and simulation to generate conflict-free timetables.These can then be simulated with random variations in departureand dwell times. This is implemented on a fictive single track linewith high speed passenger train traffic. The objective is to studyoutcome by varying allowance times and delays. Simulations arecarried out in RailSys, a software using synchronous simulationto model train traffic operations.

Place, publisher, year, edition, pages
ASME Press, 2014
National Category
Transport Systems and Logistics
Research subject
Transport Science
Identifiers
urn:nbn:se:kth:diva-168022 (URN)10.1115/JRC2014-3820 (DOI)000359389500064 ()2-s2.0-84902831696 (Scopus ID)
Conference
2014 Joint Rail Conference, JRC 2014; Colorado Springs, CO; United States;April 2014
Note

QC 20150526

Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2015-09-28Bibliographically approved
6. A simulation based framework for evaluatingeffects of infrastructure improvements onscheduled and operational delays
Open this publication in new window or tab >>A simulation based framework for evaluatingeffects of infrastructure improvements onscheduled and operational delays
2015 (English)In: 6th International Conference on Railway Operations Modelling and Analysis, International Association of Railway Operations Research , 2015Conference paper, Published paper (Refereed)
Abstract [en]

This paper aims at presenting a framework for obtaining and evaluating multiple timetablesin operational conditions on different infrastructure alternatives. Evaluating several differenttimetables, which share characteristics regarding departure frequencies, helps in gettinga more comprehensive picture of how scheduled and operational delays are affected byimprovements or reductions in the infrastructure.In order to flexibly create infrastructure alternatives a script is developed in which differentstation layouts can be defined and expanded into a railway line by connecting stationstogether. This is then compiled to files that RailSys can interpret, thereby facilitating in includingthe infrastructure as a variable in the analysis. Timetables are obtained by definingnominal train paths in a combinatorial approach and simulating these in RailSys in order toget conflict free timetable solutions.A case study is presented where the infrastructure, applied departure frequencies andsuperimposed stochastic delays are varied. Results from this give an indication of howmuch the scheduled and operational delays are improved when longer sections of a singletrack line are expanded to double track. The case study is fictive but the framework canbe used for evaluating real scenarios, e.g. where different infrastructure expansions areweighed against each other and only one of them can be realized.

Place, publisher, year, edition, pages
International Association of Railway Operations Research, 2015
Keyword
Railway, Simulation, Single track, Timetable, Delay
National Category
Transport Systems and Logistics
Research subject
Transport Science
Identifiers
urn:nbn:se:kth:diva-168024 (URN)
Conference
6th International Conference on Railway Operations Modelling and Analysis (RailTokyo)
Note

QC 20150526

Available from: 2015-05-25 Created: 2015-05-25 Last updated: 2015-05-26Bibliographically approved

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CiteExportLink to record
Permanent link

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Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
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  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
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Output format
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