GSM-R is the dedicated mobile communication system used by railways across Europe for voice contact between drivers and signallers, including on the Dutch network managed for train operations. Alarmoproep is Dutch for alarm call, the priority alert used when a message cannot wait for normal calling. A recording of the tone circulated among rail enthusiasts, simulator players and dispatch audio collectors, who share short functional railway sounds online. It remains used because it is instantly recognisable to train fans while still reading as a serious emergency alert to everyone else.