seat61.com is a great place to start for planning rail journeys across Europe.

See here for Dublin to London, and then here for London to Berlin. It doesn't look like the connections work out well to let you do it in a oner, so you'd probably need an overnight in London or Paris (or even both)

If you're not in a hurry, and want to stop off en route, and enjoy looking out of the window, then there's no reason you shouldn't consider doing this journey on the surface route.