European Railway Traffic Management System Research Articles

Digital Twins for Anomaly Detection in the Industrial Internet of Things: Conceptual Architecture and Proof-of-Concept

Modern cyber-physical systems based on the Industrial Internet of Things (IIoT) can be highly distributed and heterogeneous, and that increases the risk of failures due to misbehavior of interconnected components, or other interaction anomalies. In this paper, we introduce a conceptual architecture for IIoT anomaly detection based on the paradigms of Digital Twins (DT) and Autonomic Computing (AC), and we test it through a proof-of-concept of industrial relevance. The architecture is derived from the current state-of-the-art in DT research and leverages on the MAPE-K feedback loop of AC in order to monitor, analyze, plan, and execute appropriate reconfiguration or mitigation strategies based on the detected deviation from prescriptive behavior stored as shared knowledge. We demonstrate the approach and discuss results by using a reference operational scenario of adequate complexity and criticality within the European Railway Traffic Management System.

A Methodology Framework for Modelling a Rail Moving Block System

In the railway field, rigorous development processes contribute to implement safe and efficient systems. Railway safety standards recommend the use of formal modelling and verification techniques to guarantee processes’ correctness and validate safety requirements. ERTMS/ETCS L3 (European Railway Traffic Management System / European Train Control System Level 3) is a European standard for interoperable railways based on the concept of Moving Block signaling systems which allows for substantial capacity gains and reduced costs. In this paper, we explain why the ETCS L3 struggles to be deployed despite the benefits it can bring. Then, we discuss the planned implementations of ETCS L3 at a European-wide scale. Finally, we present a methodology framework using formal models to verify moving block systems. This work is performed in the context of the PERFORMINGRAIL European project.

Constraint-force driven control design for rail vehicle virtual coupling

This study investigates the constraint-force driven control problem of virtual coupling. To solve the constraint force, the explicit equation of vehicle motion with equality constraints is established using the Udwadia–Kalaba approach. First of all, this study introduces a brief overview of virtual coupling concepts in the European Railway Traffic Management System and some scenes of virtual coupling. The control method is proposed to enable the mechanical system to follow the designed constraint. Moreover, the dynamic model for virtual coupling problem is established. Second, combined with the dynamic model, the equation constraint is designed to make the rail vehicle movenment reach the control objective. By solving the equation based on the Udwadia–Kalaba approach, the control inputs that can render the vehicle to move along the desired trajectory. Third, numerical simulation results demonstrate the effectiveness of the proposed method in virtual coupling problem.

Asynchronous Resilient Wireless Sensor Network for Train Integrity Monitoring

To increase railway use efficiency, the European Railway Traffic Management System (ERTMS) Level 3 requires all trains to constantly and reliably self-monitor and report their integrity and track position without infrastructure support. Timely train separation detection is challenging, especially for long freight trains without electrical power on cars. Data fusion of multiple monitoring techniques is currently investigated, including distributed integrity sensing of all train couplings. We propose a wireless sensor network (WSN) topology, communication protocol, application, and sensor nodes prototypes designed for low-power timely train integrity (TI) reporting in unreliable conditions, like intermittent node operation and network association (e.g., in low environmental energy harvesting conditions) and unreliable radio links. Each train coupling is redundantly monitored by four sensors, which can help to satisfy the train collision avoidance system (TCAS) and European Committee for Electrotechnical Standardization (CENELEC) software integrity level (SIL) 4 requirements and contribute to the reliability of the asynchronous network with low rejoin overhead. A control center on the locomotive controls the WSN and receives the reports, helping the integration in railway or Internet-of-Things (IoT) applications. Software simulations of the embedded application code virtually unchanged show that the energy-optimized configurations check a 50-car TI (about 1-km long) in 3.6-s average with 0.1-s standard deviation and that more than 95% of the reports are delivered successfully with up to one-third of communications or up to 15% of the nodes failed. We also report qualitative test results for a 20-node network in different experimental conditions.

Towards safer rail control, command and signalling in the context of digitization

Aim . The state of the art of railway computer-based control, command and signalling (CCS) systems is characterized by high requirements in terms of dependability, functional safety and cybersecurity under the conditions when digital transformation and challenges associated with the demand for increased competitiveness of railway transportation force the transition to new paradigms in engineering, testing, verification, validation and standardisation to facilitate and speed up the process of development and implementation. It is expected that while preserving the level of dependability and safety, at least, as it is, the industry has to enable the maximum possible introduction of innovative solutions and digital tools aimed at further automation of CCS systems to enhance the capacity and throughput of railways and the performance of systems, to minimize the impact of the human factor and reduce the number of failures and downtimes. In this context, the key factors are the interoperability (technical and operational compatibility) of systems and the technological independence of railway operators and infrastructure managers from the designer/supplier of railway automation systems, eliminating the vendor lock-in effect. Methods . The paper gives an overview of the state of the art of railway computer-based control, command and signalling using the example of the EU and provides an analysis of these systems in terms of dependability and safety in the context of migration to new grades of automation. Results . The author has considered the evolution of control, command and signalling systems in the EU using the example of the European Railway Traffic Management System (ERTMS). The analysis covered the general trends and approaches to engineering, testing, verification, validation and standardisation of railway CCS systems. The paper has overviewed the major EU research and design programmes of CCS development with the dependability and safety methodology taken into account. A special attention has been given to the methods of open engineering, remote lab testing and standardisation of ERTMS interfaces. Conclusions . In the context of digital transformation, the development of state-of-the-art railway computer-based CCS systems implies an accelerated introduction of a whole range of innovative solutions and a wide application of commercial off-the-shelf components (COTS), thus making systems more complex and being capable of affecting the dependability parameters. In order to maintain these parameters at a specified level and to minimize the impact of human factors, the railway community is increasingly using formal methods and automated means of engineering, diagnostics and monitoring at all stages of the system’s lifecycle. A major factor of dependability is the standardisation of the system’s architecture, interfaces, open source design and testing software, including the standardisation of approaches to remote lab testing of products by different manufacturers to prove the reliability of operation at the boundaries of systems of various manufacturers.

Blockchain‐enabled virtual coupling of automatic train operation fitted mainline trains for railway traffic conflict control

Railway traffic conflicts are common in the day-to-day operation of trains due to the limited track capacity, the varying priority of trains, localised weather conditions, maintenance operations etc. The conventional conflict resolution strategy focuses on delaying the trains by considering the braking distance of a preceding train, cancellation or intermediate stopping of the trains etc. This strategy can solve the problem of railway operators than the passenger's problem of missed connecting trains, missed business opportunities or personal appointments etc. To ensure both operator and passenger satisfaction, this paper proposes a novel blockchain-enabled virtual coupling of automatic train operation fitted mainline trains for railway traffic conflicts. The immutable blockchain databases of the trains and track infrastructures help to forecast the traffic conflicts in real time. Seven variants of virtual coupling strategies are described in this study. Based on the chosen strategy, the reference model of the automatic train operation of mainline trains is virtually coupled or synchronised. Finally, the simulation results and theoretical analyses using several case studies are carried out to confirm the sufficiency of the proposed system and method. The major advantage of the proposed study is that it can be an overlay to the existing European Railway Traffic Management System Level-2.

A constructive framework for the preventive signalling maintenance crew scheduling problem in the Danish railway system

In this article, we consider the problem of planning preventive maintenance of railway signals in Denmark. This case is particularly relevant as the entire railway signalling system is currently being upgraded to the new European Railway Traffic Management System (ERTMS) standard. This upgrade has significant implications for signal maintenance scheduling in the system. We formulate the problem as a multi-depot vehicle routing and scheduling problem with time windows and synchronisation constraints, in a multi-day time schedule. The requirement that some tasks require the simultaneous presence of more than one engineer means that task synchronisation must be considered. A multi-stage constructive framework is proposed, which first distributes maintenance tasks using a clustering formulation. Following this, a Constraint Programming (CP) based approach is used to generate feasible monthly plans for large instances of practical interest. Experimental results indicate that the proposed framework can generate feasible solutions and schedule a monthly plan of up to 1000 tasks for eight crew members, in a reasonable amount of computational time.

The ON-TIME real-time railway traffic management framework: A proof-of-concept using a scalable standardised data communication architecture

Automatic real-time control of traffic perturbations has recently become a central issue for many European railway infrastructure managers. The aim is to make use of mathematical algorithms to maintain the required service availability during unplanned disturbances to operations. In the literature many tools for real-time traffic control are proposed, but their effects on traffic have never been studied neither in real life nor in fully realistic simulation environments. We can mention only a few pilot tests and a unique installation in the Lötschberg Base tunnel in Switzerland, which uses a replanning framework that is generally applicable but does not consider a standard data communication format. Standardisation of railway data is instead one of the main requirements of the European Railway Traffic Management System (ERTMS) to enable traffic interoperability across different countries along the Trans-European Transport Network (TEN-T). Following this direction, this paper introduces one of the outputs of the European project ON-TIME: a framework for the automatic real-time management of railway traffic, designed for being standard and interoperable across different European railways. We make use of a web-based Service-Oriented Architecture to ensure scalability and flexibility of application. A standard railML interface is used for the input/output data of the modules, allowing immediate applicability of the framework to any network having a railML representation. A proof-of-concept is provided where the framework is tested in a closed-loop with the simulation environment HERMES for perturbed traffic scenarios on different networks in the UK, the Netherlands and Sweden. Tests are performed for two different replanning algorithms (ROMA and RECIFE) used for the automatic detection and optimised resolution of train conflicts. The two algorithms are compared on the test case in Sweden. Results show that the design of the proposed framework is effective in managing traffic perturbations and is extendible to real-life systems.

Impact of European Railway Traffic Management System on Human Performance in Railway Operations European Findings

The safety of railway system operations depends on several internal and external factors. The former include rail traffic rules, infrastructure, rolling stock reliability, organizational safety culture, and human factors. The railway systems in Europe, North America, and Australasia have seen significant technological developments for improved capacity and efficiency. Europe, for instance, is implementing the European Railway Traffic Management System (ERTMS). However, transition to a more automated traffic management system requires, among other things, changes to infrastructure, rolling stock, operational procedures, or all three. Concerning operational procedures, the literature shows that train drivers, signalers, and controllers have the greatest effect on the safety of a railway network. Therefore, the reliability and safety integrity of the railway network are largely dependent on human factors, in particular, the performance of human operators. This performance in turn is affected by a number of factors broadly known as performance-shaping factors (PSFs), with deficiencies in communication accounting for more than 90% of incidents for the conventional railway system. Therefore, this study investigated the influence of ERTMS and in particular the Global System for Mobile Communications–Railway (GSM-R) on operators’ performance. The study analyzed 74 accident and incident reports of railway operations before and after GSM-R implementation from several European railway organizations. The results identified the communications-related factors that affected human performance in the conventional and upgraded railway system based on the existing railway-PSF taxonomy. Finally, the results showed the positive impact of GSM-R implementation on operators’ performance.

Impact of European Railway Traffic Management System on Human Performance in Railway Operations

The safety of railway system operations depends on several internal and external factors. The former include rail traffic rules, infrastructure, rolling stock reliability, organizational safety culture, and human factors. The railway systems in Europe, North America, and Australasia have seen significant technological developments for improved capacity and efficiency. Europe, for instance, is implementing the European Railway Traffic Management System (ERTMS). However, transition to a more automated traffic management system requires, among other things, changes to infrastructure, rolling stock, operational procedures, or all three. Concerning operational procedures, the literature shows that train drivers, signalers, and controllers have the greatest effect on the safety of a railway network. Therefore, the reliability and safety integrity of the railway network are largely dependent on human factors, in particular, the performance of human operators. This performance in turn is affected by a number of factors broadly known as performance-shaping factors (PSFs), with deficiencies in communication accounting for more than 90% of incidents for the conventional railway system. Therefore, this study investigated the influence of ERTMS and in particular the Global System for Mobile Communications–Railway (GSM-R) on operators' performance. The study analyzed 74 accident and incident reports of railway operations before and after GSM-R implementation from several European railway organizations. The results identified the communications-related factors that affected human performance in the conventional and upgraded railway system based on the existing railway–PSF taxonomy. Finally, the results showed the positive impact of GSM-R implementation on operators' performance.

Rail infrastructure, ITS and access charges

This paper presents an overview of the principles and technologies relating to railway infrastructure. Specifically this paper includes rail–wheel contact, inspection and maintenance of rail. Intelligent transport systems (ITS) and their applications for the purposes of the railway transport in Europe are discussed. The potential, levels of development, technological and operational characteristics of the European Railway Traffic Management System (ERTMS) are presented. Finally, a discussion on methodologies, principles and current practices for access charging in Europe is provided.

An overview of lessons learnt from ERTMS implementation in European railways

The European Union’s aspiration for railway systems that are interoperable across Europe is driven by the need to service a market that is open within and across industrial sectors and national boundaries. This in turn requires that the technologies and operational procedures that underpin the railway systems facilitate not only interoperability but also enhancement of safety, capacity and efficiency. The European Railway Traffic Management System (ERTMS) is designed to enable interoperability through use of one unique signalling system as opposed to conventional signalling systems. However, the introduction of ERTMS must be undertaken to facilitate the European wide ambition to reduce risk on the railways.This paper addresses the issues relevant to the safe introduction of ERTMS into European railway systems, with a focus on the technical and procedural challenges of moving from conventional signalling to a new traffic management system. Existing literature, augmented with a targeted survey of subject matter experts, is used for a critical appraisal of safety considerations across Europe. Differences and variations across networks and countries are identified, and used to determine the significant issues that need to be addressed to enable the safe introduction of ERTMS. Finally, generic observations are made on the factors that impact safety and human factors as a result of the introduction of new technologies and procedures into existing railway environments.

Modelling of Railway Logics for Reverse Engineering, Verification and Refactoring

Model-based approaches are widespread both in functional and non functional verification activities of critical fault-tolerant systems. Reverse engineering can also be used to support checks for correctness of system implementation against its requirements. In this paper we show how a model-based technique, using the Unified Modeling Language (UML), suits the reverse engineering of complex control logics. UML is usually exploited to drive the development of software systems, using an object-oriented and bottom-up approach; however, it can be also used to model legacy non object-oriented logic processes featuring a clear distinction between data structures and related Operations. Our case-study consists in the most important component of the European Railway Traffic Management System / European Train Control System: the Radio Block Center (RBC). The model we obtained from the logic code of the RBC significantly facilitated both structural and behavioral analyses, giving a valuable contribution to the static verification and refactoring of the software under test.

European railway traffic management system validation using UML/Petri nets modelling strategy

The European Union set up a European management system for rail traffic: the ERTMS system to ensure, in full safety, train circulation on different European networks. As the full deployment of this system is long and expensive, evolutions are necessary and raise other technological challenges. The goal is to determine how to use ERTMS specifications to produce test scenarios. This paper presents methods, models and tools dedicated to the generation of test scenarios for the validation of ERTMS components based on functional requirements. The development of ERTMS system requires adequate methods for modelling and checking its behaviour. Evaluation and certification of the system can be done by generating test scenarios applying formal methods. The Unified Modelling Language (UML) is a widely accepted modelling standard in industry. However, it is a semi-formal language and it does not allow verification of system behaviour. In this case, formal models like Petri Net can be used. These methods are used in order to formalize ERTMS specification. Tests scenarios are generated on the basis of Petri net models. One scenario is considered like a firing sequence in the reachability graph of the Petri net. Then, test scenarios are applied on ERTMS platform simulator in order to check the components and to give test verdicts. Finally, the approach, developed in this paper, has been applied to ERTMS components in order to demonstrate the validation and certification costs reduction and also to minimize the upgrade and retrofit constraints and validation cost.

Model-Based Approaches for Railway Safety, Reliability and Security: The Experience of Ansaldo STS

In order to master the increasing complexity of modern railway control systems, novel model-based approaches are needed to allow engineers to evaluate such systems against strict system-level dependability requirements. In this talk, we provide an overview of the experience of Ansaldo STS in using model-based approaches for railway safety, reliability and security. Dependability requires assessment both at the software and at the hardware levels. At the software level, models have proven useful to support both static and dynamic functional analyses in order to discover systematic faults in the code. At the hardware level, we have experimented that compositional multi-formalism modeling approaches well suit the evaluation of system safety and reliability against random faults. The use of models has allowed engineers to improve both the effectiveness and the efficiency of system verification. Views of the Unified Modeling Language have been adopted to perform informal or semi-formal analyses, while Stochastic Petri Nets, (Repairable) Fault Trees, Continuous Time Markov Chains and Bayesian Networks have been employed for formal and quantitative analyses. Analytical risk and vulnerability models have also been experimented for security assessment with respect to intentional threats and natural hazards. Due to the wide range of possible applications, we are currently studying in depth both the theoretical and the technological issues related to the multi-paradigm dependability modeling using appropriate frameworks Francesco Flammini got with honours his laurea (July 2003) and doctorate (December 2006) degrees in Computer Engineering from the University Federico II of Naples. Since October 2003 to January 2007, he has worked in Ansaldo STS as a Software/RAMS Engineer in the Verification & Validation unit, specializing in model-based dependability evaluation and testing of real-time control systems. During these years, he has been involved in several ERTMS/ETCS (European Railway Traffic Management System / European Train Control System) projects. Since February 2007, he has worked on the protection of transportation infrastructures against external threats, specializing in risk assessment and design of security management systems. In 2006/2007 he has been an Adjunct Professor of Software Engineering at the Second University of Naples. He currently teaches Computer Science at the University “Federico II” of Naples and serves as the

ERTMS — a contribution to the creation of tomorrow’s railway

This paper gives an overview of the Community’s European Railway Traffic Management System (ERTMS) programme. ERTMS is an umbrella programme that brings together three main streams of development activity in the areas of signalling and command/control (ERTMS/ETCS), telecommunications (GSM-R) and traffic management (ERTMS/ETMS).