Buffer Stops are parts of a vehicle used to connect a vehicle to a vehicle, locomotive, or locomotive, to transmit traction, braking, and cushioning longitudinal impact. It consists of a coupler, a buffer, a hook-tail frame, and a board, etc., and is installed in the traction beam at the bottom of the vehicle frame. In order to ensure the safe and reliable connection of the vehicle and the interchangeability of the coupler buffer installation, the relevant regulations for the railway rolling stock in China stipulate that the horizontal centerline of the coupler's knuckle from the rail surface is in the empty state after the coupler buffer is loaded. Passenger cars are 880mm (allow +10mm, -5mm error), and trucks are 880mm (±10mm). The difference between the maximum horizontal height of the centerline of the coupler of two adjacent vehicles shall not exceed 75mm.