Mission-critical dedicated networks of utilities such as power, railway, emergency services, etc are built on robust, deterministic and lower OPEX-based TDM technologies. With changing applications and end-user devices, these networks are destined for evolution so that they are scalable, bandwidth efficient and dynamic yet robust. This paper/presentation focuses on this evolution to Next Generation networks using technologies such as IP/MPLS, MPLS-TP and combinations. This paper also highlights the challenges posed to these technologies from legacy interfaces, ROI, manageability and practical migration planning.