Induced surges in railway signaling systems during an indirect lightning strike

This paper presents a study of lightning induced surges in railway signaling systems with the FDTD method. During an indirect lightning strike, induced surges are observed in the outdoor circuits due to electric and magnetic coupling. The induced surge currents propagate along the signal cables towards the receiving equipment in railway stations. It is found that geometry of the outdoor lines, earthing and bonding practices affect induced surge currents and voltages in the circuits. Equipotential bonding can substantially reduce the induced surge voltage impinging on the equipment in railway stations.