On December 28, 1987, the new crossover in Fuxingmen Station came in to use, splitting Phase 1 into two parts: one from Changchunjie to Beijing Railway Station, connected with Phase 2 on both ends to form a circle line; the other from Pingguoyuan to Lishilu (Nanlishilu), extended into Fuxingmen Station, making it possible to transfer between the two lines. The two new lines are called Line 1 and Line 2 nowadays. Not drawn to the scale.