The AB4RAIL Project was awarded to Radiolabs in the frame of the Shift2Rail project to study and assess the adoption of possible alternative bearers and communication protocol compatible with the  Adaptable Communication System (ACS) specified for the new FRMCS architecture destined to replace the GSM-R standard for all the railways communications.

The on-line meeting with representatives of the X2Rail project (X2RAIL-5 ( is part of the 12th COLA meeting (Collaboration Agreement with the railways community) to present the outcomes of the project and discuss the results. In this frame, Free Space Optics (FSO), High Altitude Platform Systems (HAPS), and Low Earth Orbit (LEO) High-Throughput Satellites have been analysed from the technical and economical point of view. These technologies have been selected and assessed in the AB4Rail project among the future telecommunication technologies for the integration into the existing railway infrastructure.

Results on transport protocols suited for railway scenarios were also presented and discussed as the Transport Control Protocol (TCP), User Datagram Protocol (UDP), Stream Control Transmission Protocol (SCTP), and QUIC protocol, including the analysis of HTTP and FTP (and their secure versions of HTTPS and FTPS) application protocols.

Among the others, LEO constellations have emerged as a mature and step-change technology being already deployed and expected to dominate the Satcom offerings with lower latency and worldwide coverage to complementing terrestrial solutions.

Upon these achievements and the conclusion of the AB4Rail project by the end of 2022 with an ad hoc dissemination campaign, Radiolabs is planning a follow up project to launch a comprehensive field test campaign in the operational railways environment as a further contribution to the take-off of the FRMCS standard.