For anybody who is interested in seeing some video of the U-Bahn in East
Berlin, it can be viewed here.

http://www.youtube.com/watch?v=xQOYMKNo5x0

The one thing that confuses me about this is that I noticed Giselas and
much older stock running on the same lines, whereas I thought their
width profiles were much different, requiring them to separately operate.

I also noticed what appeared to be earlier versions of Dorotas,
seemingly at Alexanderplatz.

Lastly, as East Germany was part of the Eastern bloc, why did they not
eventually operate Soviet-built metro cars?

Budpaest, Prague and Warsaw had them for their respective metros, so why
did the East Germans build the Gisela?