This part of ISO 16881 gives the requirements for the selection of the size for iron or steel wheels and presents the formulae for the local stresses in crane structures due to the effects of the wheel loads. This standard covers requirements for steel and cast iron wheels and is applicable for metallic wheel/rail contacts only. Roller bearings are not in the scope of this standard. It is to be used together with the classification of ISO 4301 series and the loads and load combinations of ISO 8686 series. It is based upon the limit state method (see ISO 8686-1). This Standard is for design purposes only and should not be seen as a guarantee of actual performance.