This European Standard describes the specific `Design for PRM Use' requirements applying to rolling stock on the Trans-European Network (TEN) covered by the TSI for PRM and the assessment of those requirements. The following applies to this standard. The definitions and requirements describe specific aspects of `Design for PRM Use' required by people with reduced mobility as defined in TSI PRM. This standard defines elements which are universally valid for obstacle free travelling including steps for access and egress and boarding aids. The definitions and requirements of this standard are used for rolling stock applications. This part of the standard covers those requirements relating to `Boarding Aids'. The standard only refers to aspects of accessibility for PRM passengers. It does not define general requirements and general definitions for specific components and systems. This standard assumes that the vehicle is in the defined operating condition, any damages or operating failures will not be taken into account when assessing these requirements. Where minimum or maximum dimensions are quoted these are absolute NOT nominal requirements. The following areas of `Accessibility of People with Reduced Mobility to rolling stock' are covered in 2 parts: Part 1 contains Steps for Access and Egress Part 2 contains Boarding aids This standard describes these areas with clear and consistent terms and definitions. Measurement methods and/or assessment procedures needed to establish a clear pass/fail assessment are provided where necessary.