The first time I played the Switch was actually on a train, as I planned to visit my parents that weekend but didn't want to miss out on Zelda. I do play it on train, if I get a seat to kill time. I played it also on the tram (now riding bike again to work, no chance to play while riding bycicle). I see sometimes people playing 3DS on the tram, and did that too. Overall, I have the 3DS more often with me, because of Streetpass and being more secure by closing it (no screen to the outside). But I do take the Switch with me, if I commute for a longer time or otherwise see the chance to play it. Hotel room works well to, but this is not exactly public.
EDIT: Oh yeah, I live in Potsdam, germany.