Hey,
Well I just returned late from conducting historical studies in Berlin, I had to go to the area around check point Charlie and spent nights in a hotel in Merringdamm, a lot of the travel was focused primarily on the trains and underground systems, I was amazed at how well they run, in my three days there, only one train was terminated and they sent another one to take the passengers in something like four minutes.
There was one specific station I believe called Haschelles...