The scheme introduced on May 6, 1902 was relatively simple: single numbers were reserved for the ring lines, two-digit for the remaining lines. Initially, the tens gave information about where the line was going; 10 lines were to be found in Moabit, 60 lines in Weissensee and 70 lines in Lichtenberg. The lines of the West Berlin suburban railway were assigned the letters A to M, the Berlin-Charlottenburg tram the letters N to Z and the lines of the Southern Berlin suburban railway were numbered with Roman numerals. The 1910 taken over by the GBS northeastern Berliner Vorortbahn received in 1913 the line designation NO. The colored signal panels remained in parallel until about 1904. In addition, the lines created during this period were still colored signal panels with new, sometimes even three-color color combinations.