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- Ranjbar, Vahid
(författare)
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Challenges for ERTMS related to implementation, technology and railway capacity
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of European Rail Traffic Management System (ERTMS) is to remove crossborder barriers and create an interoperable railway network across European countries (Smithet al. 2012). Since its birth, ERTMS has faced several issues regarding interoperability andimplementation. In addition, one of the main questions for decision-makers and infrastructuremanagers regarding ERTMS is determining what level of operation is suitable to implementand deliver additional performance compared to legacy systems.This thesis aims to identify challenges for the ERTMS related to implementation, andinteroperability to achieve a mobile and intelligent railway transport system. A subsequentstudy on railway capacity is performed. It investigates the impact of ERTMS Hybrid Level 3(HL3) compared to the European Train Control System Level 2, (ETCS L2) and a Swedishlegacy system, ATC2. To achieve the goals of this study, two methodologies are used: 1)Literature review and 2) Simulation.The literature reviews were conducted in order to determine what the challenges ofimplementation of ERTMS are to resolve issues related to ERTMS subsystems (Global Systemfor Mobile Communication – Railway (GSM-R), and ETCS). ETCS needs to exploit hybridtechnologies for gradual deployment of next generation signalling systems. GSM-R must bereplaced with new technologies such as, long-term evolution (LTE) to support necessary datatransmission capacity for implementation of the next generation of signalling system.Furthermore, the literature review regarding achieving interoperable and intelligent railwaytransport shows that reducing wayside equipment have potential to provide a more costefficientrailway transport. To test and validate this finding, it is necessary to develop adaptedtools for railway and signalling systems. Providing flexible railway operation with backwardforwardinteroperability and hybrid solutions will make it possible to gradually upgrade currentsystems.As decision-makers look for additional performance in new signalling systems over legacyinstallations, the impact various signalling systems have on line capacity must be examined.To this end, a comparative analysis between legacy ATC, ETCS Level 2, and ETCS HybridLevel 3 using simulation tool was performed. The case study was performed on a highfrequency traffic commuter train line in Stockholm during peak hours. The results of study showHL3 delivers better performance compared to the legacy system and ETCS L2, and can deliveracceptable performance for a commuter train line with high density. Considering the casestudy, it can be concluded that HL3 delivers better performance on commuter train lines withhigh density.
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| 2. |
- Vautard, Félix, 1993-
(författare)
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Improvement of departure time suitability for interregional rail timetables
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to respond to growing interregional rail traffic, rail capacity should be allocated better. To achieve this, one possibility is to optimise suitability of departure times for rail passengers in the timetabling process. The suitability of departure and arrival times refers to how well the timetable can diminish constraints on passengers that must adapt their activities to train schedules. However, current knowledge on this issue is limited. Indeed, only few studies have quantified how passengers valuate departure time suitability. These studies are also quite brief in their coverage of the influence of travellers’ profiles on these valuations. In addition, current methods comparing the socioeconomic consequences of different timetables are not applicable in all contexts, and most of them rely on strong simplifications. In summary, this thesis aims to answer the following research questions:What are the determinants for passenger valuations of departure time suitability?How to improve the welfare assessment of departure time shifts in interregional timetables?In paper 1, I focus on the first research question. To this end, we present a new study in which we estimate new valuations of departure time suitability. To achieve this, we conducted a stated-preference survey on several Swedish rail lines. We present the design of the survey and its result in the paper. With this work, I aim to fulfil two objectives: first, to provide figures to improve inputs for travel demand forecast models and socioeconomic assessments. Second, to determine the influence of trip characteristics and traveller’s socioeconomic profile on their valuations.In paper 2, I focus on the second research question. To this end, we present a method that enables calculating changes in welfare due to departure time shifts in any interregional timetable. In this method, we bridge schedule-based model forecasts with cost-benefit analysis framework. This enables a better approximation of consumer and producer surplus than in previous literature. In addition, we show the applicability and potential of our method on a case study covering a Swedish interregional line.
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| 3. |
- Johansson, Ingrid, 1990-
(författare)
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Simulation Studies for Improved Efficiency in Road and Rail Freight Transports
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The demand for road and rail freight transport continues to grow with the expanding economy, while the climate crisis requires reduction in greenhouse gas emissions. Therefore, tools and solutions for reducing fossil fuel use and enabling more efficient use of infrastructure are needed. This thesis utilises microscopic and macroscopic traffic simulation as tools to improve certain aspects of road and rail transport planning in the operational, tactical, and strategic planning time horizons.For road freight transports conducted with heavy-duty vehicles, fuel consumption can be reduced by smarter driving. Strategic planning concerning introduction of intelligent and connected vehicles is needed, along with planning of actual vehicle operations. Microscopic road traffic simulation is utilised to show that heavy-duty vehicle platooning, which lowers the fuel consumption through reduced aerodynamic drag, can be conducted on two-lane highway stretches without disturbing surrounding traffic. Further, substantial reduction of the fuel consumption can be achieved by applying fuel-optimal deceleration trajectories, assuming available information about the traffic situation ahead.Shifting freight transports from roads to railways is another possible measure to reduce emissions. Previous simulation studies of railway traffic has mainly focused on passenger trains, combined with not including freight train departures before the scheduled timetable, even though it commonly occurs in Sweden. Therefore, both microscopic and macroscopic railway traffic simulation, with and without allowing early freight train departures, is conducted in a case study. The resulting freight train punctuality is closer to empirical punctuality when early departures are included.A modal shift from road to rail transport increases capacity utilisation of railway networks, and is only possible within available capacity. Therefore, reliable methods for capacity analysis are needed. A method for capacity analysis is introduced and evaluated, with particular focus on railway station analysis. An advantage of this method is it can be used in tactical and strategic planning of future timetables and infrastructure.
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