Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A simulation based framework for evaluatingeffects of infrastructure improvements onscheduled and operational delays
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)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 [en]
Railway, Simulation, Single track, Timetable, Delay
National Category
Transport Systems and Logistics
Research subject
Transport Science
Identifiers
URN: urn:nbn:se:kth:diva-168024OAI: oai:DiVA.org:kth-168024DiVA: diva2:813957
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
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

Open Access in DiVA

fulltext(349 kB)108 downloads
File information
File name FULLTEXT01.pdfFile size 349 kBChecksum SHA-512
1b70e85d8c446e24b768f1bd2db61b1d2c7b39778e6cba0c3d49ba2855f6b0da439257e41572bd1a9587d806f5eef88df8ea45c2623e395fad5eba985c8cb42d
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Sipilä, Hans
By organisation
Transport planning, economics and engineeringThe KTH Railway Group
Transport Systems and Logistics

Search outside of DiVA

GoogleGoogle Scholar
Total: 108 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 902 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf