This volume describes the danger to telecommunication system workers and users and damage to equipment as well as the interference to transmission of information that may occur as a result of the proximity of telecommunication system installations to electric power and electrified railway installations. It also describes the conditions that may result in danger to telecommunication system workers and users or damage to equipment. It must be emphasized that although the possibility of danger may exist, the probability of damage to equipment is small and the likelihood of injury is very remote. In addition, it states the conditions that may result in interference to the transmission of information because of the influence of electrical power and electrified railway installations. The likelihood of transmission degradation is significantly increased by such factors as exposure length, earth return currents, harmonic content of power current, cable shielding and longitudinal balance.