A perplexing system for me is Cleveland's metro. It was built in a time in which Cleveland was a relevant and somewhat okay city to live in; but due to a mix of deindustrialization, people moving to the west and south as air conditioning made those places habitable, and economic focus being shifted away from the Midwest in general Cleveland's population shrunk by around 75% and this metro is barely ridden. It operates for the few thousand people a day who use it, and it goes to the airport so it's somewhat good to have. Thing is this was probably a very reasonable addition to a once typical large city, but Cleveland simply isn't that anymore so it's kind of useless. Like imagine if every random city with 300k people had an extensive internal rail network.