By the end of 2025, a consortium comprising ČD – Telematika and Kontron Transportation had completed the installation of mobile signal repeaters in Railjet, Pendolino, and InterPanter trains. Operational radio optimization took place in the spring of 2026, and all repeaters are now in operation. The Czech Railways fleet includes a total of 27 trains comprising 151 cars.
The train repeater is designed to improve communication between mobile phones and the base station of a public mobile operator on trains, thereby ensuring uninterrupted connectivity. At its core is an external antenna mounted on the roof of the train. This antenna receives signals from the public mobile networks of all operators. The signal is then fed into the Kontron RUD19-5 digital repeater, which is equipped with four independent frequency bands. The repeater utilizes digital signal processing, automatic gain control (AGC), and selective filters that enable clear separation of the bands for individual operators.
The systems being amplified are 2G/GSM, 3G/UMTS, 4G/LTE, and 5G. However, modern train repeaters are not merely “dumb amplifiers.” Given the evolving and changing infrastructure of public operators, it is essential to adjust the parameters of the radio channels. This is facilitated by a remote monitoring system, through which Czech Railways has a complete online overview of all repeaters, including their location, status, and whether everything is functioning properly. It is thus possible to remotely perform all necessary configuration adjustments and software upgrades, as well as view operational logs and measurements from the repeaters.
Another feature utilized is so-called geofencing via polygons. This allows us to determine where, in which area, the repeater will be turned on or, for security or technical reasons, turned off. The “Automatic Gain Control” feature is also very important – the repeater dynamically adjusts to the signal strength in each area, eliminating both signal overload and weak signals.
The installation of mobile signal repeaters is one of the most important steps toward modern train travel. It enables Czech Railways to offer stable mobile connectivity even on routes where frequent outages would otherwise occur due to the design of modern trains. Thanks to Kontron RUD19-5 digital technology, precise measurement, remote monitoring, and sophisticated polygon configuration, the system is also secure, reliable, and ready for the gradual rollout of fifth-generation mobile networks.
