European Train Control System Research Articles

Engineering for Critical Systems: The Automatic Train Operation over European Train Control System for Freight Trains Use Case

Engineering for Critical Systems: The Automatic Train Operation over European Train Control System for Freight Trains Use Case

Применение гармонических полуволн для автоматизации управления высокоскоростными поездами

The emergency braking processes in the European Train Control System (ETCS) of high-speed trains are associated with stepwise regulation of acceleration (deceleration) depending on the braking ability of the train, terrain data and changing weather on the route. These processes are defined in ETCS. The procedure for stepwise regulation of deceleration is carried out by the driver repeatedly in the process of braking until the train stops completely. The beginning of emergency braking and its end, as well as the braking process itself, is accompanied by repeated pulsed operation of the brakes, which leads to jumps in deceleration and, accordingly, to increased wear of the brake system, a decrease in comfort for passengers, which results in the limitation of the maximum allowable speed. The article proposes a new concept and technique for constructing mathematical models of emergency braking curves different from ETCS curves and based on harmonic half-waves. It is shown that the ETCS deceleration curves are described by known second-order power half-waves. Their joint study gives grounds to assert that the application of these curves leads to the obligatory pulsed mode of brake operation. Two new variants of models of emergency braking curves described by harmonic half-waves are proposed. The first option has one pulsed brake application at the end of the braking interval. The second option is free from braking impulses and allows the use of continuous regulation. These models explain the features of ETCS, contain proposals for their elimination, and are applicable to the development of new emergency braking curves that allow smooth control of emergency braking of trains. Efficiency, differences and advantages over ETCS braking curves are shown on the results of mathematical modeling of emergency braking processes.

A Microservices-Based Approach to Designing an Intelligent Railway Control System Architecture

The symmetry between customer expectations and operator goals, on one hand, and the digital transition of the railways, on the other hand, is one of the main factors affecting green transport sustainability. The European Train Control System (ETCS) was created to improve interoperability between different railway signaling systems and increase safety and security. While there are a lot of ETCS Level 2 deployments all over the world, the specifications of ETCS Level 3 are under development. ETCS Level 3 is expected to have a significant impact on automatic train operation, protection, and supervision. In this paper, we present an innovative control system architecture that allows the incorporation of artificial intelligence (AI)/machine learning (ML) applications. The architecture features control function virtualization and programmability. The concept of an intelligent railway controller (IRC) is introduced as being a piece of cloud software responsible for the control and optimization of railway operations. A microservices-based approach to designing the IRC’s functionality is presented. The approach was formally verified, and some of its performance metrics were identified.

HPC Platform for Railway Safety-Critical Functionalities Based on Artificial Intelligence

The automation of railroad operations is a rapidly growing industry. In 2023, a new European standard for the automated Grade of Automation (GoA) 2 over European Train Control System (ETCS) driving is anticipated. Meanwhile, railway stakeholders are already planning their research initiatives for driverless and unattended autonomous driving systems. As a result, the industry is particularly active in research regarding perception technologies based on Computer Vision (CV) and Artificial Intelligence (AI), with outstanding results at the application level. However, executing high-performance and safety-critical applications on embedded systems and in real-time is a challenge. There are not many commercially available solutions, since High-Performance Computing (HPC) platforms are typically seen as being beyond the business of safety-critical systems. This work proposes a novel safety-critical and high-performance computing platform for CV- and AI-enhanced technology execution used for automatic accurate stopping and safe passenger transfer railway functionalities. The resulting computing platform is compatible with the majority of widely-used AI inference methodologies, AI model architectures, and AI model formats thanks to its design, which enables process separation, redundant execution, and HW acceleration in a transparent manner. The proposed technology increases the portability of railway applications into embedded systems, isolates crucial operations, and effectively and securely maintains system resources.

Preparation of the User Requirements Specification for ETCS Level 2 System in Serbia - Experiences and Challenges

This paper presents a strategy implemented for preparation of the national User Requirements Specifications (URS) for European Train Control System (ETCS) with Level 2 in the Republic of Serbia. The requirements were the result of several parallel activities: gaining experience from similar implementations of the ETCS in the framework of the European TEN-T corridor railway lines, consultations about the specific technical solutions with the institutions and several suppliers of signalling equipment. The process resulted with a comprehensive specification, which will be used as a firm basis for further implementation of the ETCS system on Serbian railway network.

Formal Verification of the European Train Control System (ETCS) for Better Energy Efficiency Using a Timed and Asynchronous Model

The ERTMS/ETCS is the newest automatic train protection system. This is a system that supports the driver in driving the train. It is currently being implemented throughout the European Union. This system’s latest specifications also provide additional functions to increase the energy efficiency of train driving in the form of ATO (automatic train operation). These functions of the ETCS will be valuable, provided they operate without failure. To achieve errorless configuration of the ETCS, a methodology for automatic system verification using the IMDS (Integrated Model of Distributed Systems) formalism and the temporal tool Dedan was applied. The main contribution is asynchronous and timed verification, which appropriately models the distributed nature of the ETCS and allows the designer not only to analyze time dependencies but also to define the range of train velocities in which the operational scenario is valid. Additionally, the novelties of the presented verification methodology are the graphical design of the system components and automated verification freeing the designer from using textual design. We express the verified properties as observer automata rather than in temporal logic. Moreover, we check partial properties related to system fragments, which is crucial in distributed systems. This paper presents the verification of an example ETCS system application. The verification results are presented as sequence diagrams leading to a correct/incorrect final state.

GERALD: A novel dataset for the detection of German mainline railway signals

In recent years, a strong push towards driverless mobility solutions can be seen in many transportation sectors including railways. While the European Train Control System already specifies the necessary interfaces to open up the possibility of Automatic Train Operation (ATO) for mainline railway vehicles, required infrastructure-side upgrades of interlocking systems are time- and cost-intensive. Alternatively, a pure vehicle-side Automatic Train Operation solution can be conceptualized that relies on processing the same audio-visual input a human train driver would normally base his decisions on. This would require the vehicle-side detection of track-side railway signals to determine the vehicle’s movement authority and allowed maximum speed. Such a signal detection system could furthermore be employed as an Advanced Driver Assistance System (ADAS) or support autonomous shunting operations. To enable such a system, this paper presents GERALD, a novel dataset for a neural network based detection approach of railway signals. The dataset contains 5000 images from a wide variety of railway scenes as well as annotations for the most common types of German mainline railway signals. The material was gathered using publicly available cab-view recordings uploaded by railway enthusiasts on YouTube. Using a state of the art neural network architecture for evaluation, we notice promising detection accuracies despite GERALD being a comparably small dataset. The dataset is freely available for research and non-commercial purposes at: https://github.com/ifs-rwth-aachen/GERALD

The Effectiveness of Distributed Acoustic Sensing (DAS) for Broken Rail Detection

Broken rails remain one of the main causes of railway accidents despite improved rail quality and inspections. Today, signalling system with track circuits are often used to detect broken rails, however new signalling systems such as the European Train Control System (ETCS) with axle counters are replacing track circuits and therefore new methods are needed to detect broken rails. One promising technology is distributed acoustic sensing (DAS). The best DAS analytical techniques to show the position of the rail break are gradient analysis, convolution using the train consist and 2 D sinusoidal convolution. This paper describes field tests carried out on DAS to evaluate its ability to detect broken rails and the moment when rails break. The testing showed that DAS has good potential for detecting broken rails in both scenarios. Especially helpful is the ability of DAS to identify the moment of rail breakage and its potential for determining the break’s location on open lines. Recommendations for further research include testing these qualities in more detail and considering how DAS could be efficiently combined with new signalling systems.

New onboard train integrity and train length determination: what are the safety requirements?

In the European Train Control System level 3, using on-board control-command systems for the train integrity monitoring and length determination functionalities transfer the train operation safety responsibility from the infrastructure managers to the railway operators. To implement these safety-critical functions, quantitative and qualitative safety requirements shall be specified as stipulated in the railway safety European standards and regulations. These functions must fulfil safety integrity level SIL 4 requirements at the system level, independently from trackside infrastructure. The contribution of this paper consists in proposing a methodology to determine the safety targets of both functions in terms of Tolerable Hazard Rates (THR). The obtained THRs are then apportioned among the safety-related functions to specify the quantitative safety requirements for every functional part.

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.

Comparative analysis of the functionality of centralized and distributed LEU

This article addresses the centralized LEU (Lineside Electronic Unit) encoder used in ERTMS/ETCS Level 1 (European Rail Traffic Management System / European Train Control System). It is explained what a centralized LEU encoder is and why this solution offers more possibilities than a distributed approach. Also explained the general principle of the encoder and how it works with switchable Eurobalise. The paper also juxtaposes how it works with and connects to the interlocking system in both the distributed and centralized approaches. The differences between the centralized and decentralized LEU encoder in diagnostic and management capabilities are also described.

ETCS (ESC) and GSM-R (RSC) compatibility tests in polish conditions

Abstract: The process of verification of the installation of the ‘on-board control-command and signalling’ subsystem is complex and requires numerous and time-consuming checks of both the overall technical documentation for a given ETCS installation on a specific vehicle, as well as checks performed during in-service tests. The experience has shown that the tests carried out in laboratories in simulated conditions and the commissioning tests of the on- board and trackside subsystems do not provide sufficient certainty in terms of the correct integration of the ‘on-board control-command and signalling’ subsystem with ‘trackside control-command and signalling’ subsystem and other subsystems. Therefore, additional tests of ETCS (European Train Control System) and GSM-R (GSM for Railways) on-board configurations with trackside ETCS and GSM-R installations on railway lines were introduced (hereinafter ESC / RSC compatibility tests). The premise of the ESC compatibility tests and RSC is to facilitate the operation of new subsystems, because their correct functioning in a given environment is fully verified at the stage of demonstrating compliance of ESC and RSC. In accordance with Polish requirements, from 1 July 2021, ESC / RSC tests are obligatory for all new, renewed and modernized projects in the field of the ‘on-board control-command and signalling’ subsystem. This obligation is a big challenge for vehicle manufacturers and users, because at that time these tests had not yet been carried out on the network managed by PKP PLK S.A. Accordingly, this article aims to introduce the issues related to the ESC and RSC tests, as well as to describe the roles and responsibilities of the various parties involved. in the implementation of the tests. Keywords: ESC / RSC tests; Compatibility; ERTMS, ETCS

Impact of signalling system on capacity – Comparing legacy ATC, ETCS level 2 and ETCS hybrid level 3 systems

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.

Traffic Capacity Assessment of the Selected Track Section on the Slovak Railways Network after the Implementation of ETCS L3 Based on Signaling Principle

In the field of railway operation, it is essential to establish uniform conditions for interconnectivity requirements and compatibility of equipment in the Pan-European railway area to ensure effective interoperability. It also includes, for example, the introduction of a control system with modern and advanced interlocking systems (safety devices). The European Train Control System (ETCS) is a single European train protection system that will increase safety in rail transport. Nevertheless, this system may have an impact on the throughput on those railway lines where it is applied. The main research objective is to determine the impacts and effects of the configuration of track signaling equipment on the operational management of traffic and especially on the creation of a traffic plan. The optimization of transport processes on the railway infrastructure means creating the conditions for achieving higher throughput performance, especially including a higher number of train paths into the train traffic diagram. This paper examines and compares the impacts of ETCS and its levels (in particular ETCS L3) on the practical throughput of the selected national infrastructure manager. A heuristic procedure is used with the application of the analytical methodology of the Railways of the Slovak Republic (ŽSR), which uses the principles of mathematical statistics and probability. Significant comparative indicators are occupancy times and the degree of utilization of practical throughput. These are used in investment decisions in the modernization of line sections to achieve interoperability of the railway system.

Analysis of the possibility of implementing interoperability tests on Polish railways

Ensuring the greatest possible interoperability of rail transport, especially for railways in Europe, is one of the key projects to be implemented using the European Rail Traffic Management System (ERTMS), including the European Train Control System (ETCS) and the Global System for Mobile Communications-Railways (GSM-R). The ERTMS system aims to replace many different rail traffic control systems with one, common and unified European solution (Commission Regulation (EU) 2016/919, 2016), (Directive (EU) 2016/797, n.d.). Its creation was dictated by the desire to standardize the traffic control systems present in the territories of various European countries, at the same time extending their functionality and eliminating the existing technical barriers. The aim of this article is to present the possibility of implementation interoperability tests - IOP tests, on Polish railways. These tests are intended to provide a faster, more accurate and less costly demonstration of compliance with the ETCS interoperability requirements compared to field tests. The work defines the concept of interoperability tests as well as the purpose of their application. The general principles and procedures for conducting interoperability tests are presented. In the further part of the work, the operation of laboratories in the European Union is analysed. The laboratories functional in Switzerland and Spain were selected for this analysis. Following, the paper presents the validity of implementing interoperability tests on the territory of the Republic of Poland. On the basis of the pan-European procedure of conducting interoperability tests and the experience of foreign independent laboratories, conditions for the implementation of tests in the Polish railways were developed, which could be used in the future to introduce IOP tests in Poland.

Railway Wireless Communications Channel Characterization

Railway applications are in continuous evolution with the aim of offering a more efficient, sustainable, and safer transportation system for the users. Generally, these applications are constantly exchanging information between the systems onboard the train and the trackside through a wireless communication. Nowadays, Global System for Mobile communications-Railway (GSM-R) is the technology used by European Train Control System (ETCS), but it is becoming obsolete. Therefore, alternatives for this technology have to be found for the different railway applications. Its natural evolution is to move forward with the latest technology deployed: Long-Term Evolution (LTE), which the Public Land Mobile Networks (PLMN) have already deployed. Therefore, testing the performance of this communication technology in the railway environment could be useful to assess its suitability and reduce the cost of railway network dedicated deployment. In order to do that, a methodology to characterize the communication environment is proposed. The main goal is to measure geolocated impairments of any communication channel in a railway environment being able to determine its behavior of the different communication technologies and find out possible coverage issues. Moreover, it could help in the selection of suitable communication technology for railway. This paper presents a brief description of the communication for railways and its QoS parameters for performance measuring. Afterward, the testing methodology is described, and then, the communication channel measurement campaign on a real track in Spain where the railway environment is variable is presented (tunnels, rural/urban area…). Finally, the measurements and results on this real track in Spain are shown. The results provide suitability of the 4G technologies based on the delay requirements for the implementation of ETCS over it.

REVIEW PAPER ON POSITIVE TRAIN CONTROL TECHNOLOGY

This review paper focuses on the positive train technology also referred to as PTC (a technology which serves to ensure efficiency, safety and reliability during the train operations in the track) by automatically stopping the train when the train operator seems not to take the required appropriate action when need be, it serves mainly to get rid of accidents caused due to negligence of the train operator or inability to control the freedom of mobility of the train. It looks into the technologies such as Chinese train control systems, Communication based control systems, European train control system all of which can be considered to be part of the Positive train control, other than that, this paper tries to look into what led to creation of this system, the building units and operational layers of a complete PTC system, analyses each unit and its operations and looks further into the challenges affecting the operations of a PTC system try to explore the future trends in this field.

Development and validation of a safe communication protocol compliant to railway standards

Railway systems are composed of a multitude of subsystems, sensors, and actuators that exchange datagrams through safety-critical communication protocols. However, the vast majority of these protocols rely on ad hoc interlacing mechanisms and safety codes which raise the heterogeneity and complexity of the overarching railway system. Therefore, Rete Ferroviaria Italiana, the company who is in charge of managing the Italian railway network, coordinated the definition of the Protocollo Vitale Standard (Standard Vital Protocol). This protocol is inspired to, and compliant with, the communication protocols adopted for the European Train Control System (ETCS) (SUBSET, UNISIG, 037, Euroradio FIS, version 2.3. 0; SUBSET, UNISIG, 098, RBC-RBC safe communication interface, 2007), and it is meant to become the standard layer to enable safe communication between components of the Italian railway system. This paper reports our experience in the design, implementation, verification, and validation of the Protocollo Vitale Standard in compliance with the European safety standards for railway systems. We first defined a safety plan and a verification and validation plan, which guide the design, development, verification, and validation activities as required by safety standards. Guidelines of such plans have been followed strictly until completion of the work, which concludes with the provision of a safety case where all safety evidences are summarized. Noticeably, we (i) selected appropriate safety mechanisms, (ii) verified the software design, (iii) implemented the software in compliance with code metrics and coding rules, (iv) conducted tests to validate the protocol against its functional and performance requirements, and ultimately (v) devised all relevant documentation and a safety case which summarizes the evidences needed for certification.

Railway Capacity Enhancement with Modern Signalling Systems – A Literature Review

In times of ever stronger awareness of environmental protection and potentiation of a beneficial modal split, the railway sector with efficient asset utilization and proper investment planning has the highest chance of meeting customer expectations and attracting new users more effectively. Continuous increase in railway demand leads to an increase in the utilization of railway infrastructure, and the inevitable lack of capacity, a burning problem that many national railways are continually facing. To address it more effectively, this paper reviews available methodologies for railway capacity determination and techniques for its enhancement in the recent scientific literature. Particular focus is given to the possibility of increasing railway capacity through signalling systems and installing the European Train Control System (ETCS). The most important relationships with segments of existing research have been identified, and in line with this, the directions for a potential continuation of research are suggested.

Developing a new Safety Risk Model (SRM) methodology for the GB rail industry

This paper presents research recently undertaken by RSSB to develop a new Safety Risk Model (SRM) methodology. The SRM provides a network-wide risk profile for the mainline railway in Great Britain (GB) and has underpinned the industry’s evidence and risk-based approach to safety management for the best part of two decades. Firstly, users’ requirements were identified, collated and prioritised. The current SRM was then reviewed, summarised and appraised against these requirements to determine areas where there was potential to improve the current methodology. Potential new methodologies were then investigated to determine whether there were any which may enable the new SRM to better meet current user requirements. The feasibility and potential benefits of these alternative methodologies were assessed to determine the best approach for building the new SRM. This paper gives an overview and understanding of the processes that have been carried out in this research and will be of interest to others who may wish to undertake a similar appraisal of their risk models. Abbreviations: ALARP: as low as reasonably practicable; ALCRM: all level crossing risk model; BN: Bayesian network; CBA: cost benefit analysis; ETCS: European train control system; FWI: fatalities and weighted injuries; GB: Great Britain; HAZID: hazard identification; HEM: hazardous event movement accident; HEN: hazardous event non-movement accident; HET: hazardous event train accident; HS2: High Speed 2; PIM: Precursor Indicator Model; RPT: Risk Profile Tool; RSSB: Rail Safety & Standard Board; SMIS: safety management intelligence system; SRM: Safety Risk Model; SWOT: strengths, weaknesses, opportunities and threats