You kid, and it would be kinda horrible in certain ways, but I genuinely think it would increase ridership significantly.
Let's face it, classism right now manifests as:
* poor folk use terrible public transit
* med income folk drive cars
* high income/wealth folk get driven around by robots or staff
At least with the classist train you cut down on emissions and public funds spent fixing roads. And I'd argue it's a bit less unequal than the status quo in 95% of the US.