This document is applicable to vehicles equipped with buffers and screw coupling systems. In order to allow operation and coupling of trainsets or vehicles, this document specifies the defined free space for the shunter called the "Berne rectangle" and the necessary free space for the installation of the rescue coupler. This document specifies the location, fixing and free spaces on the headstock of: - buffers; - screw coupling systems; - end cocks; - pneumatic half couplings; - connections for electric cables. It also specifies the calculation of the width of the buffer heads. Unless otherwise displayed, all dimensions given in this document are nominal values.