The Central Line in London has some of its stations designed in this way, and you can certainly feel the slope when the train enters or leaves the station.

After riding the Central Line frequently for one year I got used to that feeling and start to think that there is something missing when I ride other lines...

I would assume the incline would be impossible without seeing the horizon, because the car also accelerates. I guess you mean the increased gravity feeling at the bottom of the track?

Right. I traveled once on a long-distance bus line that acted like a zero-gravity plane for a split second, as it went over a bump in the road. Just wondering if the experience would be comparable :)