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  • 1.
    Ranjbar, Vahid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Challenges for ERTMS related to implementation, technology and railway capacity2021Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    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.
    Ranjbar, Vahid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Migration to ERTMS for dense traffic lines: investigation methodologies and application to the Stockholm Citybanan case study2021In: Tecnoscienza: Italian Journal of Science and Technology Studies, E-ISSN 2038-3460, Vol. 76, no 12, p. 937-977Article in journal (Refereed)
    Abstract [en]

    Capacity of infrastructure in Railway dependson several factors, between them Control Commandand Signalling (CCS) systems aim at providing improvedoperation by keeping constant safety performances. Thisstudy intends to investigate the effects of ERTMS Level 3on capacity in comparison to ERTMS Level 2 and Swedishsignalling system ATC2. The study includes a comparativeevaluation based on both recognized microscopic simulationtools and analytical methods, adapted for the specificpurposes. The selected case study is the Southbound of cityline in Stockholm (Citybanan) in the peak period undervarious timetable configurations. The study findings illustratequantitatively the increase of capacity achievable byERTMS Level 3.

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  • 3.
    Ranjbar, Vahid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Olsson, Nils O.E.
    Key challenges of European Rail traffic Management System2020In: Proceedings of TRA2020, the 8th Transport Research Arena: Rethinking transport – towards clean and inclusive mobility, 2020Conference paper (Refereed)
    Abstract [en]

    This study is designed to analyse key challenges to European Rail Traffic Management System (ERTMS) implementation encountered in recent years. To achieve this goal, a systematic literature review was conducted where data were gathered and analysed concerning challenges and current issues relating to ERTMS implementation projects. The findings show a growing literature of ERTMS experiences, especially in the last 4 years. Several European countries have contributed to the literature, which appears to be primarily based on qualitative research methods. To reduce complexity created by a plurality of actors, definition of a single regulatory entity to address uniformity and safety assessment of rolling stock, and deployment of wayside equipment is necessary. Concerning technical issues, outcomes show that interaction between the European Train Control System (ETCS) and Global System for Mobile Communications – Railway (GSM-R) requires replacing these with new hybrid technologies moving towards long-term evolution (LTE) and modular approaches.

  • 4.
    Ranjbar, Vahid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Olsson, Nils O.E.
    Towards mobile and intelligent railway transport: A review of recent ERTMS related research2020In: Computers in Railways XVII, WITPRESS LTD. , 2020, Vol. 199, p. 65-73Conference paper (Other academic)
    Abstract [en]

    The development of the European Railway Traffic Management System (ERTMS) throughout Europe over the last two decades to remove obstacles to providing an interoperable railway network has been facing several challenges. This study briefly highlights several of these challenges by analysing the current architecture of ERTMS and main concerns such as its implementation, the interoperability of communication, formal methods, hybrid ERMS (Level 3), safety, and human factors. This study has taken a systematic approach to data collection and analysis through a review of the current literature. The studies examined illustrate that it is necessary to reduce the number of components in order to pivot the system toward mobile equipment, autonomous trains, and decentralised communication. In the area of formalisation, every supplier and responsible party conducting modelling and testing of the system uses a different tool. Here, we conclude it would be appropriate to develop a robust and reliable tool for modelling, formalisation, testing and the validation of critical safety systems in the railway industry according to its particular specifications and functionalities, e.g. for ERTMS L3, including moving block, virtual coupling and Automatic Train Operation (ATO). To bridge gaps between human operation and new technologies, reduce human error, and increase performance in the railway industry, a stronger emphasis on the development of employees’ skills with new technologies is highly recommended. In order to build upon previous investments in ERTMS and to guarantee backwards and forwards interoperability, it is necessary to exploit hybrid solutions and to gradually update the current systems.

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  • 5.
    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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1 - 5 of 5
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