In 1990, a new tramway to Buitenveldert and Amstelveen was ready to go. Line 5 links Station Zuid with Amstelveen Binnenhof, while line 51 ran as a light rail service, from Station Zuid to Amstelveen Poortwachter, and later to Westwijk in 2004. Also in 1990, line 9 to the Watergraafsmeer was extended to Diemen (Sniep). In 1991, a rush hour line 20 and a special events line 11 were opened. In 1993 a support line 11 and in 1997 a circle line 20 were added to the network. Lines 6, 11 (2 lines) and 20 have since disappeared. However, line 11 is still used occasionally for extra services to the RAI convention centre.