Telecommunications play a critically important role in the digitisation of railways both in the more traditional areas of operational communications and in more innovative areas such as those for train running schedule control.

GSM-Railway is a radio communication system for railways standardised at the European level and used globally, mainly for communication between trains and control centres. It is a part of ERTMS (European Rail Traffic Management System).

Based on GSM technology, so as to benefit from its economy of scale and be a cost-effective alternative to the numerous and non-interoperable alternative solutions used in the past, the network has been developed since 2004 and is set to cover about 11,000 kilometers of rail lines (conventional and HS/HC) in 2021, including more than 1,000 km in tunnels.

The GSM-R network-based ground-to-train service enables voice, SMS and data communications between Infrastructure Manager and Railway Companies personnel, providing specific features such as functional number calling, group and emergency rail calls, location-dependent addressing, priority level management.

In addition, on railway lines equipped with European-standard ERTMS signalling and traffic control, which was developed to ensure the safe and seamless movement between the railway networks of different European countries that have the same technology, the GSM-R network provides the transmissive data channel for communication between the on-board and trackside command, control and signalling technology systems.