What I saw on the roof of the high-speed rail seemed to be some kind of laser, which kept flashing. Excuse me, who knows what this is?

This is a high-speed video camera, which is called "Vehicle-mounted OCS Running State Detection Device" (referred to as "3C"). By installing a vehicle-mounted OCS running state detection device on the roof of the operating EMU, the OCS running state is monitored along with the operation of the operating EMU, and the full coverage and all-weather dynamic detection of the OCS state of the high-speed railway is realized. This is very helpful for the high-speed rail power supply department to check the abnormal faults of pantograph and catenary. By analyzing the shot video, we can judge whether the pantograph and catenary state of the train running section are normal, and guide the power supply department to check the catenary state.