The Georgetown/Silver Plume loop railway...once a part of a railroad network between mining towns in the Colorado Rockies. Now, a historical reminder, popular with families and school groups.
Colorado is still very much a train state, even now. Listening to the forlorn and thrilling moan and whistle of trains in the night is possibly my favorite thing about living in Denver, with its working trainyards. Working trains and "ski trains" are still active through the mountain corridors, and Denver is still to some extent an active hub for train travel, as is Grand Junction.
Colorado's current presence in the midst of its own history is one of the reasons I so deeply love this state.