The network hard disk video recorder adopts a 19-inch 2U standard cabinet with a full metal shell and good electromagnetic compatibility. It is fully adapted to the use environment on the train. The network hard disk video recorder consists of a chassis and a power module installed in the chassis, an NVR motherboard and a mechanical hard disk module. It has the characteristics of simple structure, modular functions, easy operation and maintenance, etc. It is mainly used for on-board video monitoring and storage in the rail transportation industry.