With rail transit intervals becoming shorter, the traditional manual control of train speeds can no longer meet the necessary requirements. Rail transit operation and control have transitioned from early manual operations to fully automated and computer-controlled stages.

The protection focus for line and station equipment is on electromechanical equipment and communication systems, which consist of multiple complex and interrelated subsystems. These include the Power Supply System, video surveillance systems, Automatic Fare Collection System, Fire Alarm System (FAS), Building Automation System (BAS), Rail Transit Network Command Center, Platform Screen Door Control System, Communication System, Passenger Information System, and Vehicle Management and Control System.

Considering the impact of electromagnetic pulses on the reliability of system operations, it's important to do lightning protection for all equipment or cables related to the relevant systems such as power supply systems, video surveillance systems, wireless communication systems, broadcasting systems, clock systems and passenger information systems.

The power supply systems: use different types of surge protectors (Class II) installed in segments and properly grounded to achieve lightning protection effects for the supply system. Please refer to the following diagram.

The video surveillance systems: for communication signals, lightning protection mainly relies on installing matching signal surge protectors at the equipment's input and output ports and grounding them. This is to achieve voltage reduction and discharge, protecting the equipment from overvoltage and surge impacts. Refer to this CCTV lightning protection diagram.