Different activities are carried out by expert organisations as Notified Bodies, Dedicated Bodies, Assessment Bodies and Independent Safety Assessors in railway technology. Sometimes, these activities are called verification, sometimes assessment. So, it is necessary to distinguish not only the basis of the expertise as technical specification for interoperability or standards for functional safety, but also to distinguish the method of expertise. In this paper we will explain what independent safety assessment means, how it differs from verification in the light of the railway safety standards. Experience from practical work is provided for several activities. This concerns the assessment of the system description, hazard identification, safety architecture, safety management process, quantitative analyses, the safety case, software aspects and audits. The examples deal with what to focus on when assessing important documents as safety plan, safety case, hazard analyses, quantitative analyses or software. Also, the role of the safety manager is discussed