This document describes the procedure applied by UIC to assess the conformity of railway products. The conformity of products is assessed against the TSIs, ENs and UIC leaflets in which the product requirements are detailed. If a product passes the conformity assessment it is awarded the "UIC seal of approval" (or "UIC label"). The present document defines the requirements for the parties involved in the procedure, in particular: the applicant for the "UIC seal of approval", the UIC body responsible for the product (referred to hereafter as "UIC body"), the UIC experts, the laboratories and test centres.