The diploma thesis deals with the growth of inherent reliability in rail vehicles. Suitable methods and models for describing and predicting reliability growth are to be developed. Based on a well-founded literature search, relevant sets of standards, definitions around the terms reliability, availability and maintenance, as well as necessary statistical procedures for the representation of failure behaviour of technical systems are explained. In order to be able to implement the collected knowledge, an anonymous project will first be used in a practical part. A comprehensive reliability analysis is created from a database of faults using suitable tools and then examined with regard to reliability growth. Subsequently, two previously researched models are used to predict reliability targets and tested based on a previously defined use case. After discussion of the results, a concept for the integration of a reliability growth program into the development process of rail vehicles is described.