So, the worldwide standard for railway gauge is 1435 mm, and most tram/streetcar networks use that. However, another popular gauge for trams is 1000 mm. In some cities, it's possible to have two independent tram networks with different gauges.
My question is: do you think it could be tagged differently? I want them to be rendered differently, but I don't know which tag to use. I considered S-Bahn (light rail), but I don't think that's a good solution (for example, if I already have light rail in my city).
Any thoughts or ideas?
EDIT: The conclusion is that it's better to make a map in the wiki than render it in OGF.