This European Standard defines a set of reference masses for specifying the requirements for the design, testing, acceptance, marking, delivery and operation of rail vehicles. The reference masses defined in this document are as follows: dead mass; design mass in working order; design mass under normal payload; design mass under exceptional payload; operational mass in working order; operational mass under normal payload; These reference masses are defined with respect to the whole vehicle, but they can also apply to a specific system or component. The specification of values for tolerances applicable to reference masses is not in the scope of this standard. Tolerances can be required by an application standard. Additional loadings due to environmental factors, for example snow and retained or absorbed rainwater, are not in the scope of this European Standard.