This part of ISO 10972 establishes the particular requirements relating to mechanisms for bridge and gantry cranes, as defined in ISO 4306-1. The general requirements for mechanisms for cranes are given in ISO 10972-1. These particular requirements concern a) the general layout and design of mechanisms; b) the selection and/or design requirements of components; c) the instructions for manufacturing, mounting, installation and testing. Rules for proof of competence calculations regarding different limit states (yield strength, fatigue, wear) are excluded from this part of ISO 10972.