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  • 1.
    Fröidh, Oskar
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Warg, Jennifer
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Capacity for express trains on mixed traffic lines2014In: International Journal of Rail Transportation, ISSN 2324-8386, Vol. 2, no 1, p. 17-27Article in journal (Refereed)
    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.

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  • 2.
    Johansson, Ingrid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Palmqvist, Carl-William
    Lund University, Department of Technology and Society.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Warg, Jennifer
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Bohlin, Markus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Microscopic and macroscopic simulation of early freight train departuresManuscript (preprint) (Other academic)
    Abstract [en]

    In Sweden and other countries it is not an uncommon practice that freight trains depart more or less on-demand instead of strictly following a pre-planned timetable. However, the systematic effects of freight trains departing late or, in particular, early has long been a contested issue. Although some microscopic simulation tools currently have the capability to evaluate the effect of freight trains departing before schedule, it has yet not been established how macroscopic simulation tools, capable of fast simulation of nation-wide networks, can manage such tasks. This paper uses a case study on a line between two large freight yards in Sweden to investigate how the results of microscopic and macroscopic simulation, represented by two modern simulation tools, differ when it comes to this particular problem. The main findings are that both the microscopic and the macroscopic tools could replicate the empirical punctuality fairly well, with the macroscopic case study results being closer to the empirical data. Furthermore, allowing early departures of freight trains increased overall freight train punctuality without any major impact on passenger train punctuality, as determined by both tools. The results are encouraging, but further studies are needed to determine if macroscopic simulation is on-par with microscopic simulation.

  • 3.
    Johansson, Ingrid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Palmqvist, Carl-William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. Lund Univ, Fac Engn, Box 118, SE-22100 Lund, Sweden..
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Warg, Jennifer
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Bohlin, Markus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Microscopic and macroscopic simulation of early freight train departures2022In: Journal of Rail Transport Planning & Management, ISSN 2210-9706, E-ISSN 2210-9714, Vol. 21, article id 100295Article in journal (Refereed)
    Abstract [en]

    In Sweden and other countries it is not an uncommon practice that freight trains depart more or less on-demand instead of strictly following a pre-planned timetable. However, the systematic effects of freight trains departing late or (in particular) early has long been a contested issue. Although some microscopic simulation tools currently have the capability to evaluate the effect of freight trains departing before schedule, it has yet not been established how macroscopic simulation tools, capable of fast simulation of nation-wide networks, can manage such tasks. This paper uses a case study on a line between two large freight yards in Sweden to investigate how the results of microscopic and macroscopic simulation, represented by two modern simulation tools, differ when it comes to this particular problem. The main findings are that both the microscopic and the macroscopic tools replicated the empirical punctuality fairly well. Furthermore, allowing early departures of freight trains increased overall freight train punctuality while the passenger train punctuality decreased slightly, as determined by both tools. The results are encouraging, but further studies are needed to determine if macroscopic simulation is on-par with microscopic simulation.

  • 4.
    Johansson, Ingrid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Sipilä, Hans
    KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group. KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Palmqvist, Carl-William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group. Lund University, Faculty of Engineering.
    Simulating the Punctuality Impacts of Early Freight Train Departures2022In: Proceedings of The 13th World Congress on Railway Research (WCRR), 2022Conference paper (Refereed)
    Abstract [en]

    Railway traffic usually adheres to a timetable, but in Sweden, around two-thirds of the freight trains depart before they are scheduled, often by hours. Even though they occur in real operations, early departures have rarely been included in simulation studies and the effects on punctuality are not fully investigated. With a macroscopic simulation tool such as PROTON, large networks can be simulated in a short time, which makes the simulation process easier. This paper uses the tool PROTON to perform a macroscopic simulation case study on the Swedish Western mainline to investigate how early departures of freight trains affect punctuality. The resulting output is a marginal overall punctuality improvement of about +0.5 percentage points. In addition, different levels of primary run time and dwell time delays have been used as simulation input, based on empirical data. The resulting ratio between primary and secondary delays appears to vary greatly between different train types, but overall about 30% were primary and 70% secondary. Future work includes modelling and calibration of departure deviations, which vary more between different train types, and where it is more difficult to separate between primary and secondary delays. Separating distributions based on train type or location will also be considered.

  • 5.
    Lindfeldt, Anders
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Användning av tågpassagedata för estimering av primära störningsfördelningar2016Report (Other academic)
    Abstract [sv]

    Syftet med detta PM är att presentera metoder för estimering av primära linje- och uppehållsfördelningar (störningar) för användning i simulering. Metoderna bygger på användning av Trafikverkets tågpassagedata.

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  • 6.
    Lindfeldt, Anders
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Simulation of freight train operations with departures ahead of schedule2014In: Comprail 2012, WIT Press, 2014Conference 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.

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  • 7.
    Minbashi, Niloofar
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Palmqvist, Carl-William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Bohlin, Markus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Kordnejad, Behzad
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Machine learning-assisted macro simulation for yard arrival prediction2023In: Journal of Rail Transport Planning & Management, ISSN 2210-9706, E-ISSN 2210-9714, Vol. 25, article id 100368Article in journal (Refereed)
    Abstract [en]

    Increasing the modal share of the single wagonload transport in Europe requires improving the reliability and predictability of freight trains running between the yards. In this paper, we propose a novel machine learning-assisted macro simulation framework to increase the predictability of yard departures and arrivals. Machine learning is applied through a random forest algorithm to implement a yard departure prediction model. Our yard departure prediction approach is less complex compared to previous yard simulation approaches, and provides an accuracy level of 92% in predictions. Then, departure predictions assist a macro simulation network model (PROTON) to predict arrivals to the succeeding yards. We tested this framework using data from a stretch between two main yards in Sweden; our experiments show that the current framework performs better than the timetable and a basic machine learning arrival prediction model by R2 of 0.48 and a mean absolute error of 35 minutes. Our current results indicate that combination of approaches, including yard and network interactions, can yield competitive results for complex yard arrival time prediction tasks which can assist yard operators and infrastructure managers in yard re-planning processes and yard-network coordination respectively.

  • 8.
    Nelldal, Bo-Lennart
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics, Traffic and Logistics. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Lindfeldt, Olov
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics, Traffic and Logistics. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics, Traffic and Logistics. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Wolfmaier, Johannes
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics, Traffic and Logistics. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Förbättrad punktlighet på X2000: analys med hjälp av simulering2008Report (Other academic)
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  • 9.
    Palmqvist, Carl-William
    et al.
    Faculty of Engineering, Lund University, Box 118, SE-221 00 Lund, Sweden.
    Johansson, Ingrid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Sipilä, Hans
    KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    A method to separate primary and secondary train delays in past and future timetables using macroscopic simulation2023In: Transportation Research Interdisciplinary Perspectives, ISSN 2590-1982, Vol. 17, p. 100747-100747, article id 100747Article in journal (Refereed)
    Abstract [en]

    Punctuality is a key factor in railway operations and is affected by both primary and secondary delays to differing degrees. Being able to separate these two types of delays is very important when simulating operations, and when conducting punctuality improvement efforts. However, it is not easy to estimate the relative proportions of primary versus secondary delays using historical data. In this paper, we demonstrate a method that uses repeated runs of a macroscopic simulation tool to estimate what share of delays has been primary or secondary. Using the Swedish region of Skåne as a case study, we estimate that about 36% of delays in 2019 were primary, leaving 64% as secondary. We further show that in order for operations to reach the targeted level of punctuality, 95% instead of the observed 87%, primary delays would have had to be cut by half. Using a draft timetable for 2025, we also simulate what the punctuality would be given different assumptions of primary delays. Assuming the same level of primary delays in 2025 as in 2019, we estimate that the punctuality would drop by a further 5 percentage points due to increased density of operations. In order to reach the punctuality target of 95% in 2025, primary delays would instead need to be reduced by two-thirds. At the request of the infrastructure manager, we also show the predicted geographical distribution of secondary delays in this future timetable. Our results highlight the need for drastic delay reduction measures to reach set targets.

  • 10.
    Ranjbar, Vahid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Olsson, Nils O.E.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Impact of signalling system on capacity – Comparing legacy ATC, ETCS Level 2 and ETCS Hybrid Level 3 systems2022In: Journal of Rail Transport Planning & Management, ISSN 2210-9706, E-ISSN 2210-9714, Vol. 23, article id 100322Article in journal (Refereed)
    Abstract [en]

    Most railways use fixed block technology, which could be replaced with moving block technology with associated high cost. It is therefore interesting to gradually upgrade the signalling system exploiting hybrid technologies. This paper aims to investigate the impact on capacity of various signalling systems (including fixed block technology and hybrid technology) using a microscopic simulation tool under scheduled (static) conditions without considering probability functions. To perform comparative analysis between European Train Control System (ETCS) Hybrid Level 3, ETCS Level 2, and the Swedish ATC2 legacy system, three signalling system scenarios are designed and capacity consumption is considered as a performance indicator. The study was performed on the central section of Stockholm’s commuter train network with peak hour conditions from the 2020 timetable. The results show that ETCS L2 delivers lower capacity consumption in total compared to the ATC2 legacy system. ETCS Hybrid Level 3 with existing trackside train detection and partially shortened block sections delivers lower capacity consumption compared to ETCS L2 and ATC2. The implementation of hybrid solutions such as ETCS Hybrid Level 3 in addition to allowing for gradual upgrading of signalling systems to the next generation (moving block system) can improve capacity of high-density commuter lines.

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  • 11.
    Sipilä, Hans
    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.
    A simulation based framework for evaluatingeffects of infrastructure improvements onscheduled and operational delays2015In: 6th International Conference on Railway Operations Modelling and Analysis, International Association of Railway Operations Research , 2015Conference 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.

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  • 12.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Calibration of Simulation Model on the Southern Main Line in Sweden2011Conference 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.

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  • 13.
    Sipilä, Hans
    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.
    Evaluation of single track timetables using simulation2014In: IEEE/ASME 2014 Joint Rail Conference, ASME Press, 2014Conference 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.

  • 14.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    HESE: Headway och signalpunktplaceringar i ETCS L22022Report (Other academic)
    Abstract [sv]

    Projektet har genomförts inom branschprogram KAJT (Kapacitet i Järnvägstrafiken). Projektets huvudsyfte är att utveckla ett verktyg (en modell) som kan användas som stöd för att göra headwayberäkningar i ETCS level 2 (ETCS L2). Verktyget ska modellera broms- och ingripandekurvor enligt de specifikationer som gäller för Baseline 3.6.0 och beskrivs i ERA Subset-26-3 [1]. När dessa beräknats för en viss bansträcka och antagna fordonstyper kan teknisk headway beräknas för respektive signalsträcka. Teknisk headway är den minsta tid som måste finnas mellan två på varandra följande tåg vid respektive signalpunkt (signalsträcka). Tiden beror på en kombination av signalpunkternas placeringar, signalsystemsparametrar, bankarakteristik (hastigheter, lutningar) och fordonsparametrar.

    Idén med verktyget är att flera parametrar enkelt ska kunna varieras och framför allt att påverkan av signalpunkternas placeringar relativt enkelt ska kunna undersökas systematiskt. Beroende på hur många olika uppsättningar av placeringar som läggs in kan headway beräknas för flera fall samtidigt och jämföras mot varandra. Ett typiskt fall att undersöka, givet en grunduppsättning av signalpunktsplaceringar, är om teknisk headway kan minskas på vissa platser och med hur mycket om placeringen ändras för en eller flera signalpunkter och/eller om en eller flera nya punkter läggs in. En grunduppsättning kan vara föreslagna signalpunktsplaceringar i ett förprojekteringsskede och exempelvis vara i stort sett samma som nuvarande signalplaceringar i ATC (1:1 principen) eller vara ett första placeringsförslag på en framtida bana. Alternativt skapas en helt fiktiv bana på vilken headwayberäkningar görs.

    Liknande analyser kan göras i exempelvis RailSys men hanteringen med att variera olika parametrar är betydligt mer omständlig och tar tid. RailSys är inte utformat för att enkelt och relativt snabbt kunna skapa och beräkna olika kombinationer av signalpunktsplaceringar.

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  • 15.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Körtidsberäkningar för Gröna tåget: Analys av tågkonfigurationer2008Report (Other academic)
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  • 16.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics, Traffic and Logistics. KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Simulation of modified timetables for high speed trains Stockholm-Göteborg2010In: Road and Rail Infrastructure / [ed] Stjepan Lakušić, University of Zagreb , 2010Conference 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.

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  • 17.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Simulation of rail traffic: applications with timetable construction and delay modelling2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis covers both applications where simulation is used on parts of the Swedish rail networks and running time calculations for future high-speed trains with top speed improvements on existing lines. Calculations are part of a subproject within the Green Train research program (Gröna tåget). Higher speeds are possible with increased cant and cant deficiency in curves. Data for circular curve radii is used on existing lines combined with information on decided and on-going upgrades. Calculation of static speed profiles is made for a set of cant and cant deficiency values. Different train characteristics are used regarding top speed, starting acceleration and power to ton ratio. Running time calculations are made for these different train characteristics with the fictive speed profiles. In addition, different stopping patterns are applied. Results are presented together with running times for two reference train types, one with carbody tilting and one without. It is clear that carbody tilting, allowing a higher cant deficiency, is important on many of the existing lines considering achieved running times. The benefit of tilting is marginal on newly built and future lines designed with large curve radii. However, on many of the existing lines the over 20 year old reference train with carbody tilting achieves shorter running times compared to a future train without tilt but with higher top speed. The work presented here has contributed with input to other projects and applications within the research program. Simulation in RailSys is used to evaluate on-time performance for high-speed trains, between Stockholm and Göteborg in Sweden, and changes in timetable allowances and buffer times with respect to other trains. Results show that ontime performance can be improved with increased allowances or buffer times. In the case with increased buffers, other trains are pushed in the timetable with the intention of obtaining at least five minutes at critical places (e.g. conflicting train paths at stations) and as separation on line sections. On-time performance is evaluated both on aggregated (group) level and for trains individually. Some of the trains benefit significantly from the applied measures. Prior to a simulation some of the delays have to be defined. This includes dwell extensions and entry delays, i.e. extended exchange times at stations and delayed origin station departures inside or at the network border. Evaluation of observed data give insight on the performance of a real network. However, separating primary (exogenous) and secondary (knock-on) delays is not straightforward. Typically the probabilities and levels of primary delays are defined as input, thus secondary delays are created in the simulations. Although some classification of delays exist in observed data, it is not sufficient without further assumptions and preparation. A method for estimating primary running time extensions is presented and applied on a real timetable between Katrineholm and Hässleholm in Sweden. The approach consist of creating distributions based on deviations from scheduled running time. Since this represent total outcome, i.e. both primary and knock-on delays are included, the distributions are reduced by a certain percentage and applied in the simulations. Reduction is done in four steps, separately for passenger and freight trains. Root mean square error (RMSE) is used for comparing mean and standard deviation values between simulated and observed data. Results show that a reasonably good fit can be obtained. Freight services show a higher variation than passenger train evaluation groups. Some explanations for this are difficulties in capturing the variations in train weights and speeds and absence of shunting operations in the model. In reality, freight trains can also frequently depart ahead of schedule and this effect is not captured in the simulations. However, focus is mostly on passenger trains and their on-time performance. If a good enough agreement and operational behaviour is achieved for them, a lower agreement for freight trains may be accepted.

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  • 18.
    Sipilä, Hans
    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.
    Simulation of rail traffic: Methods for timetable construction,delay modeling and infrastructure evaluation2015Doctoral 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.

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    Thesis
  • 19.
    Sipilä, Hans
    KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group. KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Simulations with PROTON and RailSys: Use of a macroscopic and microscopicrailway simulation tool in Swedish applications2023Report (Other academic)
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  • 20.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Simuleringsmetoder i RailSys tillämpat på Södra stambanan2012Conference paper (Other academic)
  • 21.
    Sipilä, Hans
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics, Traffic and Logistics. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Tidtabellsläggning med hjälp av simulering: Effekter av olika tillägg och marginaler på X2000-tågen Stockholm-Göteborg2009Report (Other academic)
    Abstract [sv]

    Tågresandet på X2000 (X2) mellan Stockholm och Göteborg har ökat kraftigt de senaste åren. Trafiken är idag förhållandevis tät med avgångar varje timme under större delen av dagen, kompletterad med nonstop-tåg under högtrafik. Den hårt ansträngda kapaciteten på Västra stambanan medför att de snabbaste tågen drabbas extra hårt eftersom relativt sett stora hastighetssänkningar ibland krävs vid störningar. Blandningen mellan långsamma godståg och regionaltåg samt snabbare persontåg är ogynnsam ur kapacitetssynpunkt.

    Genom simulering av störd trafik undersöks hur olika tidtabellsändringar påverkar punktligheten för X2. Tidtabell som används som utgångsläge är T09. Punktlighet definieras som rätt tid+fem minuter (RT+5). De huvudalternativ som utreds är dels en ändring av befintlig körtidsmarginal genom att lägga till respektive ta bort fyra minuter. Dessutom görs en ändring som syftar till att där det behövs öka tåglägeskanalerna för X2 för att erhålla fem minuters marginal mot andra tåg.

    Resultaten visar att om körtidsmarginalen ökas med fyra minuter höjs punktligheten vid ankomst till Göteborg från 78 till 82 % och från 74 till 83 % vid ankomst till Stockholm. Vid en minskning av körtidsmarginalen med fyra minuter sjunker ankomstpunktligheten till 69 respektive 65 %.

    Tåglägeskanalerna uppfyller i många fall redan kravet på fem minuter mot andratåg men där de inte gör det görs ändringar i tidtabellen i syfte att uppnå önskad separation mellan tågen. Ändringar på andra tåg har dock genomförts på ett realistiskt sätt utan alltför stor tidsförskjutning. I de flesta fall handlar det om justeringar på ett par minuter. Några godståg får ändrade förbigångsstationer, vilket kan innebära att deras totala gångtid förlängs. Simuleringsresultaten visar på marginell förbättring för X2 mot Göteborg. I den andra riktningen uppnås en ökning från 74 till 83 % vid ankomst till Stockholm.

    Några av X2-tågen mot Stockholm får en punktlighetsminskning mellan Gnesta och Södertälje vilket beror på att tågordningen ibland ändras mellan X2 och pendeltåg som går från Gnesta till Södertälje. I flera fall är den tidtabellslagda tidsskillnaden mellan passerande X2 och avgående pendeltåg tre minuter. Redan vid en liten försening för X2 riskeras att tågordningen ändras vilket medför att det långsammare pendeltåget hamnar framför och en ytterligare merförsening erhålls. Simuleringsresultat visar att redan om tidsskillnaden ökas till fem minuter uppnås en betydande förbättring.

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  • 22.
    Sipilä, Hans
    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.
    Timetable Generation on Single Track Lines Using Combinatorics and Simulation2013Conference paper (Refereed)
    Abstract [en]

    Timetable construction on lines with dense and heterogeneous traffic can be demanding. Mixing freight and passenger trains on single-track lines adds complexity in scheduling. Simulation offers a way of estimating operational outcome prior to establishing the actual timetable. Realistic modelling of delays is important in simulations. Exogenous delays can cause knock-on effects between trains, i.e. delay propagation.

    Many scheduling approaches do not study the expected operational outcome, similarly simulation studies are mostly done on a small number of timetables. This paper presents a method that combines generation and simulation of timetables by using a combinatorial approach as input data to a simulation software and letting it compute corresponding solutions. Measures of performance in choosing timetables for further studies can be amount of scheduled delay, requirements on cyclic patterns etc. In the next step chosen timetables can be simulated with perturbations and give insight of expected operational performance. This can in turn be used to give a more general assessment of possible capacity on a line.

    The method is applied on a fictive single track line but the same principles could also be used on double tracks. Simulation software RailSys is used in this study, among its users are for example operators, infrastructure managers and universities. RailSys offers no built in method for generating a large number of different timetables but it includes a powerful simulation module.

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  • 23.
    Sipilä, Hans
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Warg, Jennifer
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Kapacitetsanalys av Södra stambanan: Effekter av ökad trafik och ökad hastighet från 200 till 250 km/h2012Report (Other academic)
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