Information and Communication Technologies can support the progressive digitalization of the railways sector improving its efficiency and sustainability. In particular, Service Orchestration and Network Function Virtualization can push forward a paramount evolution of railways Traffic Management Systems (TMS) allowing remote operations of their different components, reducing their complexity and improving their effectiveness and scalability. In this paper the architecture of a new generation TMS based on micro-services supported by Service Orchestration and Network Function Virtualization is presented. It allows highly flexible and re-configurable networks and services, through the implementation of a service as a general replicable function available in a Virtual Machine or a container within a remote data center or a local general purpose fog node, improving the efficiency of railways control and management systems.