None. Why would you think that? My guess is you're an American living nowhere near an urban rail system but I thought most people here would at least be passing familiar with modern trains. Even some American cities have them.
Why the ad hominem?
I've lived and travelled in a ton of places. Trains in low density cities are simply not working well enough. I now prefer to live in exurb and drive everywhere. It's so good.
>modern trains. Even some American cities have them.
Which American cities have notable modern train systems? Not Portland, or NYC, or Washington DC.