The Railway industry is facing a productivity issue as is often publicised with regular delays in rolling stock projects . Plus, there is a growing need for innovation in remote services and management that have become the new normal during the COVID-19 pandemic. It drives a need for better Systems Engineering (SE) methods which include increased automation and dependence between systems and system performance, increasing number of disparate specialist engineering teams.  The aim of this paper is to develop an adaptable model which expresses the operational behavior of a train system in different railway environments, this model will be quickly and accurately configured to a specific environment to define the needs for a specific passenger service mission. Preventing late changes (cost and time-saving) by generating the right system requirements at the very early design phase through agile Model-Based Systems Engineering (MBSE) approach is the key benefit. Another goal includes increased productivity by minimizing unnecessary manual transcription of concepts when coordinating the work of large teams. This Generic* functional model of a Rolling Stock system can be configured to define specific products for an operator or Original Equipment Manufacturer (OEM).