To avoid human disasters
Railway tunnels are one of the most dangerous confined spaces that thousands of people pass through every day. In case of accidents, the probability of human disaster is extremely high : in addition of the crash, fire or smoke can kill.
Reliable critical communications
In case of intervention, emergency services as Fire Brigades, Ambulances, Police, Army, need a robust and reliable radio coverage system to communicate inside railway tunnels with the same efficiency as outside. A destroyed train can be a fantastic metal heap that will block the communication if the electromagnetic field is not enough powerful.