Abstract: A mechanical central buffer coupling for a so-called model Scharfenberg for rail vehicles which have a main conduit connected to a coupling lock in a brake actuator coupling lock, comprises a controlled pneumatic valve for opening the lock which is characterized by an air valve connected with the main air conduit and to the pneumatic valve. The air valve is connected to the brake actuator so that in case of unintentional severing of the central buffer coupling the air valve actuates the brake of the rail vehicle by venting the main conduit. The model Scharfenberg mechanical central buffer coupling generally includes an arrangement of a rotary pivotable lever system between two mechanical coupling members in such a way that the mechanical coupling members can pivot even without moving the lever system, so as to make possible an actuation of the air-shut off member only upon actuating the releasing device of the coupling members but not heretofore upon an unintentional severing of the coupling members.