You should have hung around later in Berlin - I was stationed there from 82-85 - Infantry.
We had lots of run ins with the Soviets.
I rode both the US and British duty trains to the West, often. Our battalion deployed to the Gap that way, as well as Hohenfels and other garden spots. The Brit train was great - early morning run, excellent breakfast..
While you were there, did the Commies ever just announce and then enforce that they were stopping most West Germany to West Berlin trains, inspecting them, and denying access for most train cargos (including construction materials, etc)?