The main problem i have with duolingo is that it translates to English, which is not my native language. Just to dampen my frustration about being in the red with another of my translations which is turned dwn because of some nuance..i just think that even when having all the declensions wrong...you are still understood when your vocabulary is in order. And just a small comment to he native speakers: isn't streetcar American, where the English go for tram?
I'm native AmE, and I grew up in the US in the Philadelphia area. The word there was "trolley," but I don't know if it was used elsewhere. I became familiar with the word "streetcar" somewhere along the line, but I never heard "tram" until I traveled in Europe.
To your point about Duo's translations to English, I can't even imagine trying to learn a second language through a course that teaches it in a third language, so I'm pretty impressed by your being here, Duo craziness and all! :-)
For train standing see https://www.google.com/search?q=%22train%20standing%22&tbm=bks&lr=lang_en