I have used both "tram" and "streetcar," and both have been accepted. With regard to "streetcar," looks like it may be (or have been) a US thing: https://en.oxforddictionaries.com/definition/streetcar
Yikes -- I forgot about "trolley"! Then we have "trolleybus" and "trolley car"... no end to the fun with this one! :-)
But we are talking about those intercity trains that function like buses but drive on rails? I know my question is stupid, but I have never heard the term “streetcar”; in Germany and Austria, we too tend to call them “trams”. Streetcar sounds unfamiliar to me, but again, I live in a wholly different environment.
But this is exactly what I meant by a tram, but maybe I call them by a wrong name. I think I would even call the “Schwebebahn” (magnetic railway tram) in Wuppertal by this name, even though it does not ride on railways on the streets, but it still navigates intercity. But I see I understood it correctly, but simply were unfamiliar with the name of a streetcar.
Thanks for the help!
True, the dictionary meaning generally seems to refer to the tracks, when defining tramway, but if you have a look at the wikipedia article for "tram", you will see that meaning is not so clear cut. Tramway can refer to the whole system (rail network plus trolleys), which makes it a good candidate for this instance, because I read this sentence rather as "Why don't you use the tramway service?" in general and not specifically "Why don't you take this particular trolley?"