During the Cold War and the division of Berlin, the Friedrichstraße station, despite being located in East Berlin, was utilized by two intersecting West Berlin S-Bahn lines and the West Berlin subway line U6. The station served as a transfer point for these lines, and trains stopped there, although all of the other East Berlin stations on those lines (ghost stations - Geisterbahnhöfe) were closed, where trains passed through without stopping under the watchful eyes of armed guards. At Friedrichstraße station, West Berlin passengers could transfer from one platform to another (on the West Berlin lines) but could not cross into East Berlin without the appropriate papers. The section of the station open to West Berlin lines was heavily guarded and was sealed off from the smaller portion which served as a terminus of the East Berlin S-Bahn and as a station for long-distance trains. The station was often a point where families and loved ones were split, and the small transfer building next to it was given the dubious moniker the "Tränenpalast" ("Tear Palace").