For a German postwar urban diorama scene, I wanted to put a set of streetcar rails in the street. I was curious about size of the original rails and the distance between them. Also, should I assume standard gauges in different cities? Thank you.

Germany used standard gauge rail.. I would think the street cars would be standard gauge also..

Yep, I believe it's 1,435 mm (4 ft 8½ in) too..

http://en.wikipedia.org/wiki/Tram

http://en.wikipedia.org/wiki/Trams_in_Germany#Stadtbahn

http://en.wikipedia.org/wiki/List_of_town_tramway_systems_in_Germany

You can always buy the Custom Dioramas street with street tracks in it.
Mike

Ah, but I plan to use the method of constructing cobblestone streets using cork I've seen elsewhere on this forum. Therefor it would be most practical to simply use plastic rails for teh streetcar tracks.

Real Rail Review

As model railroading is one of my other hobbies, I've looked into this quite a bit in the past. Someday I'll use all of my Piko stuff from the DDR and use it in a nice post war dio. Anyway...Not all streetcar rails in Germany were standard. Some cities ran 1 m gauge. Even more interesting, some ran dual gauge, which has been done in several countries, including the US.
Dual gauge rail uses three rails, a common rail on the left, the standard gauge rail on the right, and inboard of that, (one meter from the left rail) the right hand rail for the narrower gauge. Rare still is the use of four rails, the narrow gauge pair being centered between the standard gauge.
It might be interesting to portray the dual gauge rails, as no one else (at least in the military modeling community) has done so.
Vielleicht koennen unsere deutsce Freunde etwas behilflich sein?

The multi-rail idea sounds intriguing, though I'll probably stick to the conventional setup for what I have.