I only knew about non-computer semaphores from the Swallows and Amazons books (which are from the 1930s and 1940s). If my mom hadn't read those books to me as a child, I don't know that I'd have come across the concept.

"Token ring" is something I learned in networking, and the Wikipedia article doesn't mention railroads at all. I assume that's where the term comes from, but I only heard about railway signalling tokens decades later. (I think they may have appeared in the Thomas the Tank Engine stories on Shining Time Station, but I was quite young at the time.)