The link between the fast-moving train and the broader fixed trackside infrastructure has always been one of the key components of a train communications network. A major rail operator in Japan sought to build a trackside infrastructure that will offer a corridor of wireless coverage on and around the track. This would give the wireless clients on the train constant high-speed connectivity to support applications both onboard and along the rail line. There are numerous issues to face before this network is ready to tackle challenging CBTC operations: - seamless roaming is needed to provide uninterrupted communications, - EMI/EMC compliance is critical to ensure that there is no system performance degradation due to harsh wayside operating conditions. System Requirements • Constant high-speed connectivity along the track • Optimized AP coverage along a 20 km route • Seamless roaming between trackside APs • Open standards secure future upgrade path • Compliant with rolling stock and trackside standards