After the administrative separation of the BVG initially only changed the numbering scheme. Tram lines running from the east to the west of Berlin kept their number after the grid separation in 1953 and as a result of network thinning, individual lines were disappeared. The BVG-West waived from July 1966, the prefix A on the bus lines, the BVG-Ost waived on 1 January 1968. While in the west tram traffic was stopped 15 months later, the passenger in the east could not tell from the line number whether it was a tram or bus line. The Berliner Verkehrsbetriebe therefore planned to systematise their network in the 1970s. The city center lines of the tram should receive the line numbers 1 to 30, in Köpenick should retain their 80s numbers. The remaining numbers were intended for the bus. Night lines received from 1973 uniformly 100 numbers, for the tram were initially provided only the numbers from 120. The conversion of the daily lines was only partially completed.