What is the largest city in the US without passenger rail service?

Isn't it crazy to think that a major city still doesn't have passenger rail service? I mean, we're talking about Columbus, Ohio! The biggest city in the US without it. It's mind-boggling. I was just reading about this, and, honestly, it kind of blew my mind. You'd think in this day and age… right? I remember visiting a friend in Denver a few years back, and their light rail system was so convenient. Zipping around town, no traffic hassles. Why can't Columbus have something similar? What's the deal? I'm sure there are a ton of complex reasons – probably funding, politics, who knows… but still. It just seems odd. A city that size, so vibrant and growing, and yet… no trains for people. I bet it makes commuting a real pain. Imagine the impact it could have if they did have a decent rail system!