This paper describes how the Timed Automata Modeling Environment (TAME) has been modified to provide a formal model for Time Transition Models (TTMs) in the PVS proof checker. State-event equivalences (extensions of Milner's observation equivalences) are also formalized in PVS for state-event labeled transition systems (SELTS), the underlying semantic model of TTMs. These theories are used to verify a real-time control system.