Best sites for Railways

I'm taking up a thread from the interests section and starting a new one here. We like visiting steam railways if we happen to be on a site that's near one. One of my favourites is the Talyllyn railway near Towyn, wonderful trip into the hills, which we've visited from the Gwern-y-Bwlch site. We also like the tiny Woody Bay railway not far from Brook Lea in North Devon......any favourites out there?