Actually Detroit did start building its own subway in 1929, right before the great depression. There is no record of it on the Internet. No one in current city government knows a thing about it.

My father remembers it being built, he would have been 13. A short stretch of tunnel and the beginnings of what would have been two stations.

When I was in college in the seventies some urban explorers found an entrance. But the city managed to get it closed. The only story on it was an alt weekly, long since gone.

One of these days I am going to spend some time in the Detroit library system and dig up proof and publish it on the web.