Hehe, in one of my library books, I found the short story "A Subway Named Moebius" by A.J. Deutsch. It's a neat story on how the Boston subway system accidentally reaches topological complexity and subway trains start disappearing. (Sadly, I couldn't find the text on the Internet, but it's worth digging for in whatever library system happens to be near you.)
Of course, the whole way through reading the story, my head was happily adding the background music:
Did he ever return No he never returned And his fate is still unlearned...
Because, dammit, no story about the Boston subway system is ever complete without Charlie.