The tram line, already planned in 1988,[2] was opened at the end of 1997, following the inauguration of the Getty Center. The tram consists of air-cushioned, cable-driven vehicles that are driverless. Seismically designed, the track is an elevated structure reinforced by grade beam sections. An earthquake of a 6.8 magnitude struck Northridge, California only 11 days after the tram was completed on January 6, 1994. However, the structure showed no signs of damage.[3]