GSM-R, Global System for Mobile Communications – Railway or GSM-Railway is an international wireless communications standard for railway communication and applications.
A sub-system of European Rail Traffic Management System (ERTMS), it is used for communication between train and railway regulation control centers. The system is based on GSM and EIRENE – MORANE specifications which guarantee performance at speeds up to 500 km/h (310 mph), without any communication loss.
GSM-R could be supplanted by LTE-R,[1] with the first production implementation being in South Korea.[2] However, LTE is generally considered to be a "4G" protocol, and the UIC's Future Railway Mobile Communication System (FRMCS) program[3] is considering moving to something "5G"-based (specifically 3GPP R15/16, i.e. 5G NR),[4] thus skipping two technological generations.[5][6]