Ground-Train Radio of the French National Railways.

The system described was designed to enable two-way radio telephone conversations to be made between the drivers of trains in motion on the one hand and traffic controllers, sub-station supervisors and staff at certain stations on the other, as well as between the drivers of trains in the same radio section. The equipment also enables a driver to set off a ″radio warning″ if there is an immediate danger to traffic. An alarm signal is received by the traffic controller if a train is stopped by the automatic vigilance device. The article explains how the system functions and its advantages, particularly as regards safety and the free flow of traffic. It contains a technical description of the equipment and its operation.