It is fun, but buggy + doesn’t have great performance in some areas. I’ve recently played it for a bit on 1.1 patch drop, and lasted for about 6 hours until I hit a brick wall of a progression blocking bug. There was a decently large thread about it on the forum, no dev response, no fix in the next 3 hotfixes, so I stopped playing. Might come back for 1.3 or something.
…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.