Francesco Rispoli

On the suitability of public mobile networks for supporting train control/management systems

Telecommunications are strategic for train control system operations. The European ERTMS/ETCS system for high speed trains control utilizes dedicated GSM-R mobile network(s). The costs for deployment and maintenance of GSM-R network are not sustainable for the extension of train control to low/medium traffic lines. This paper investigates on the possibility of replacing dedicated mobile radio infrastructures with the radio network integrating one (or more) existing PLMNs and satellite as backup. A methodology for performance assessment is presented and applied to the study of network availability and operational costs. Availability can be improved by allowing train to intelligently select the public network(s) time by time. Operational costs are dictated by the satellite component which may become essential in rural areas. Looking at the European scenario, a discussion on the extension of the Euroradio protocol to operate over multi-bearer mobile network is also presented.

Integrated Public Mobile Radio Networks/Satellite for Future Railway Communications

The European train control system employs GSM-R for communications between trains and the command/control centers. GSM-R technology is quite old and will be replaced in the near future by other technologies offering less expensive solutions, especially for regional and local lines. This article investigates a new telecommunication solution based on multi radio bearers using cellular and satellite public networks as an alternative to the deployment of a dedicated infrastructure. A test campaign on a 300 km of rail line (about 10,000 km of tests) has been carried out to evaluate the performance of cellular and satellite networks in a railway environment. Test trial results presented and discussed in this article have been used to assess the performance of a multipath TCP protocol to effectively support multi-bearer communications. A discussion of the economic benefits and the potential industrial implications of the proposed solution concludes the article.

Innovative train control systems based on ERTMS and satellite-public TLC networks

The European Rail Train Management System (ERTMS) developed by the European industry represents a de-facto standard widely accepted in the world for signaling and speed-control applications. Whilst ERTMS has demonstrated its advantages as a cost-efficient train control system for high-speed lines and main corridors, the next challenge is to fulfill the emerging demand of low traffic lines for which the economical sustainability becomes a priority. Since an important share of the ERTMS operational costs are due to the telecommunication infrastructure and the wayside equipments, wireless IP-based telecom and satellite localization technologies are candidate to replace the costly fixed infrastructures. This paper discusses the scenario of local and regional lines in Europe and underlines the expected benefits brought by the adoption of the public cellular/satellite telecom network and the EGNOS-GALILEO satellite positioning system in the ERTMS ecosystem. A roadmap to validate the new technologies in the Italian Test Site is also presented.

The Adoption of Public Telecom Services for the Evolution of the ERTMS-ETCS Train Control Systems: Challenges and Opportunities

The ERTMS-ETCS train control system relies on the GSM-R dedicated radio network for train to ground communications and on terrestrial dedicated network(s) for communications between the control center and the wayside equipments. However GSM-R technology will become obsolete in the next years, has limited capacity to accommodate growing traffic needs and is suffering from interference caused by the LTE. With the introduction of IP technology in the evolution path of the ERTMS-ETCS a number of possible alternatives are being analyzed and, among them we have studied an hybrid telecom system based on public networks (cellular + satellite). Although public cellular services are provided as best-effort, satellite can act as intelligent backup to complement the cellular networks and, all together, provide QoS in line with the ERTMS-ETCS requirements. This paper outlines the results of a specific test campaign to assess the performance of the cellular networks and satellite communications in a 300 km railways line for a cumulative 18,000 travelled Km in 21 days. These results, have been processed to estimate the achievable performance in the rail environment and to pave the way for realizing the multi-bearer solution. An economical assessment of the multi-bearer solution is presented making reference to the local and regional lines for which the deployment of a dedicated network is difficult to justify.

A roadmap for the adoption of space assets for train control systems: The Test Site in Sardinia

This paper deals with the introduction and exploitation of space technologies based on the ERTMS (European Railways Train Management System) architecture bundling the EGNOS-Galileo infrastructures in the train control system, in order to improve performance and enhancing safety, reducing the investments on the railways circuitry and its maintenance. These solutions can be successfully applied for local and regional lines and low traffic lines, where the issue for a railroad enhanced service, requires increasingly financing to maintain and improve infrastructure. In order to assess the performance and validate the space technologies in a real railways environment, a special focus will be dedicated to the case of the regional lines in Sardinia where is a plan to deploy a Test Site.

A multiple satellite fault detection approach for railway environment

The aim of this work is related to railway sector and particularly with the introduction of the GNSS (Global Navigation Satellite System) into that environment. More in details, our aim is to evaluate system performance in terms of integrity of the navigation data. In the train control system, the integrity is one of the most challenge feature to achieve. Under that assumption, an algorithm that is able to exclude multiple SIS (Signal in Space) faults has been designed. In the design of the approach a multi-constellation framework has been taken into account. Simulation results highlighted promising outcomes both in terms of detection probability and in terms of false alarm rate.

A GNSS based solution for supporting virtual block operations in train control systems

This paper deals with the adoption of GNSS (Global Navigation Satellite System) applications for the evolution of ERTMS (European Railway Traffic Management System) system. We have studied a solution to monitor the train integrity and to accurately locate the position where the last coach of the train is stopped when a failure causes the split of the train into two sections. Train integrity is mandatory for the introduction of the “moving block” functionality foreseen by ETCS (European Train Control System) Level 3 that will bring major long-term benefits in terms of maintenance and operational capacity. The novelty of our approach lies in the exploitation of the multi-constellation capability to fast detect the train split with the shortest distance between the departed train sections compatible with the highest safety conditions set by the ETCS standard. The results are presented in a parametric form by varying the number of constellations and the probability of false detection and missed detection.