GSMR
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.
Read more about GSMR: History, GSM-R Uses