You can tell I don't live in a big city--my first thought was, "What's a straphanger?" I figured it's pronounced "straffanger."
I know what you mean. I grew up in a big city (Chicago) and hanged on many a strap, but seeing that compound word there, unhyphenated and unspaced, made me do a double-take too. I was thinking either a town in Norway (like Stavanger) or a disease: "He died of a straph infection."