Tracked

If they are raised, the sides should be a darkened, rusty brown color.  The top of the track where the street car's wheels contact it should be a bright, dark steel color.

 If they are inset track, where just the tops are above ground, the top only should be bright, dark steel as well.

Old model railroader here. Gino's second photo is the most common or street rails. Those are grooved rails, the tops are bright steel silver and the groove is street crap colored. Black works well.

I'm a retired NYCTA supervisor. Both pics from Gino are great and the colors they've recommended are quite right. But if the tracks have not been used; since it is 1945 Berlin that you want to depict, and if it has rained, then I would paint them a rust or the brown-rust color of the side of the raised railroad tracks. The silver/steel color of rails is only prevalent when they are under constant use from trains, trams or streetcars which in actuality are polishing the rails. So now you have an idea of which way you want to go. If those rails have not been used in over a week due to constant bombing from allied aircraft and there's been moisture in the air I'd recommend the rust color.