Like a car, a temporal engine would be able to change the speed and direction at which we travel through time.
What makes time go faster and slower? Perception and speed, especially the speed of light.
We can see back into the past through the immense distances of space. Light brings messages from the past and sends messages from us into the future, most efficiently through a vacuum. Sound also carries messages through media other than vacuum.
Accurate descriptions facilitate solutions. Using the description time bridge rather than wormhole leads directly to the understanding that a bridge would have to be built of material other than the end points. A bridge between times would have to be made out of material that is not time based, or temporal.
Things that are not temporal have no beginning and no end; they are eternal. Things that are eternal were not created or made and are generally the abstracts like Evil, and like Truth and Peace, and God. Interestingly, Evil and truth have no meaning to inanimate objects. Abstract concepts have relevance and apply to sentience and intelligence only.