A main concern in the initial phases of the development of a system t o be built is capturing the system requirements and expressing them as an adequate model, either formal or informal. In subsequent phases of the development of the system this model is used as reference for transformation steps. In this paper we describe a reasonably successful experimental strategy for the implementation of real-time systems, starting from a formal Specification, resulting in an Ada 95 implementation ofthe system and we evaluate the approach based upon practical experiences.