The coupler is used to the connection between the locomotive and the vehicle or between the vehicle and the vehicle, to transmit the traction and impact forces, and to maintain a certain distance between the vehicles. The coupler is divided into an upper top unlock type and a bottom unlock type according to the opening manner. The top unlock type is adopted by the lifting mechanism of the upper part of the hook of coupler (the general wagon adopts this type); the bottom unlock type (the passenger car adopts) is realized by the action of pushing the top lever of the lower part of the coupler hook head.

Standard：AAR M-201 Grade E/E+ TB/T 3212 Grade C/E
Standard：AAR M-211/205 TB/T 456