Plans for an extension southeast towards Rodrigo de Araya were postponed after a major earthquake in 1985; in fact, only two stations opened separately at the line's northern end in 1987 (Santa Ana and Puente Cal y Canto). Two decades later, with a change of plans, it was decided that Line 2 would continue northwards instead of southeast, owing to recent availability of Tunnel Boring Machines, and on September 8, 2004, two further stations opened to the north, Patronato and Cerro Blanco. These stations marked a new feat in Santiago and overall Chilean engineering by building under the Mapocho River and the Costanera Norte freeway. That year, the line was also extended to the south with the opening of El Parrón and La Cisterna.