Search

The railway sector has been characterized by important innovations regarding digital technologies for train-to-ground communications. The actual GSM-R system is considered an obsolescent technology expected to be dismissed by 2030. The future communication systems in the rail sectors, such as Adaptable Communication Systems (ACS) and Future Railway Mobile Communication Systems (FRMCS), can manage different bearers as 4G/5G terrestrial technologies and satellites. In this environment, the new High Throughput Satellite (HTS) Low-Earth Orbit (LEO) constellations promise very interesting performances from data rate and coverage points of view. The paper analyzes the LEO constellations of Starlink and OneWeb using public data. The Rome–Florence railway line is considered for simulations. The results evidence the LEO satellite can provide interesting performance in terms of visibility, service connectivity, and traffic capacities (up to 1 Gbps). This feature enables the LEO to fully manage a high amount of data, especially in the railway scenarios of the next years when video data applications will be more present. [ABSTRACT FROM AUTHOR]

• Experimental dynamic testing of real reinforced concreted railways girder bridges. • Multilevel modeling approach for finite element description of the bridge responses. • Analysis of the mechanical interaction between adjacent simple supported spans. • Model updating based on measured data for calibration of the mechanical parameters. This paper presents the results of an extensive experimental campaign conducted on high-speed railway girder bridges along the Rome-Florence railway line. The campaign includes material characterization and in-situ dynamic tests, incorporating vibration signals from both ambient-induced activities and train passages. The study focuses on the modeling and simulation procedures necessary for analyzing existing railway girder bridges, considering the dynamic interaction between adjacent simple supported spans. The degree of coupling caused by railroad equipment can lead to interaction phenomena, such as vibrations corresponding to mode shapes encompassing multiple spans, observed along the bridge. A multilevel modeling strategy is proposed, starting with a single span to identify the most accurate and computationally efficient approaches (frame-based, shell-based, or mixed). Subsequently, full-scale and reduced-order models of the entire structures are developed, considering the connections between rails, superstructure, and piers, to study the interaction between adjacent spans. Three case studies are presented to demonstrate the general validity of the proposed approaches, comparing the numerical results with experimental outcomes obtained from the in-situ tests. [ABSTRACT FROM AUTHOR]