The TES universe already has Cannons, Ballistae, seige-weapons etc etc, they are just not rendered in game, like alot of things.
Seems like a rather huge and mass-affecting part of the world to simply not be rendered in the game.
Or rather, it's a theme that was present in previous titles (Redguard, Daggerfall), that the series has steadily moved away from ever since Morrowind.
On the subject of the Dwemer tech, the Dwemer don't make tech. They make mythic constructs with metal wrapping paper, whose true purposes are far more esoteric and divine-reaching than that of tech as we understand it. So I don't see taking and utilizing what they made in an overtly practical sense.
Though the steampunk fan in me is more inclined to see that railway in a deep dwemer citadel...