Line 3 was initially planned for construction after Lines 1 and 2 but the 1985 Algarrobo earthquake near Santiago meant work on the new line had to be postponed so that the resources could be used to rebuild the damage caused by the earthquake. In the 1990s, Santiago's transportation needs changed dramatically with a population explosion in the south of the city, especially the communes of La Florida, Chile and Puente Alto, and the plans for Line 3 were postponed again in favour of Line 5, Line 4 and Line 4A in the south.