The Light Rail Transit (LRT), also known as the Light Rapid Transit, is the light rail component of Singapore's rail network, consisting of localised rail systems acting as feeder services to the Mass Rapid Transit network. The first LRT line was opened in 1999 and the system has since expanded to three lines, each serving a public housing estate, namely Bukit Panjang, Sengkang and Punggol. Trains on these lines link to the MRT network at Choa Chu Kang, Sengkang and Punggol stations respectively while the Bukit Panjang LRT links to a second MRT station, Bukit Panjang.