Are the questions about choosing the game system for given social situation on-topic here?
As example, I would like to ask, which game is good for the train travel in the group 4 to 8 people, which travel duration 3 to 8 hours? The game should be possible to finish in a few hours and should not require much place. But... is such question on-topic on this SE, or rather is adequate for other SE?
So long as you abide by our System Recommendation guidelines, you'll be fine. Just make sure that there's a way to assess which game is best. Asking "What game doesn't need much space" will get you the usual suspects of FATE, various flavours of basic D&D, and the small games of choice (like minimus). Make sure that we can narrow down the list.
We already have one question that's very much that sort of question: Which role-playing systems might be best suited for use over a road-trip?
It's possible to see this sort of question as being "too localized" and therefore outside the scope of the site's purpose. On the other hand, it is very much solving a real problem, and it can be useful to other people. We also have lots of recommendation questions for things like certain age groups or time frames, and no-one has raised any concerns about those being too specific. Solving a real problem seems to trump localization unless it's really only ever going to help one person.
