I had a N3DS, it was my first handheld and it was great! Really good selection of games. My most played were Monster Hunter Generations (which was my introduction to the series) and Fantasy Life - one of my absolute faves, a charming and colorful fantasy adventure with life sim elements. The story is a bit meh but the gameplay loop is incredibly satisfying and there’s nothing else quite like it. I’ve been replaying it on an emulator (rip Yuzu/Citra devs) recently and it’s still a blast.
…yes? That’s how physics works (provided that that something is moving at a constant velocity). The only difference between an enclosed moving platform and unenclosed one is that there may be additional issues with the wind/surrounding air, but the train in this post isn’t moving fast enough for that to be a concern.