Model train enthusiast David K. Smith has built a miniscule train layout which works –
the train travels in an ellipse, including through a “mountain.”
He explains: “The modeling scale would be an eye-popping 1:35,200, and the finished layout would measure .125 by .200 inches—or, roughly one third the size of its predecessor. I very nearly abandoned the project just based on these numbers; fortunately, I tried anyway.”
Not really a train, sadly. But very cute.