
The 9 V system ran from 1991 to 2006 and is still a favourite with LEGO train fans. The rails have metal tops that carry the current from a speed regulator to a motor under the locomotive, so trains could run without batteries for as long as they stayed on the track. It started with 4558 Metroliner in 1991.
1998 LEGO Sets
1998 marked LEGO’s leap into programmable play with the launch of LEGO Mindstorms, combining motors, sensors, and code for user-built robots. LEGO also entered digital entertainment with games like LEGO Creator, LEGO Loco, and LEGO Chess. New themes included Adventurers, following Johnny Thunder’s global expeditions, and Insectoids, a sci-fi successor to Exploriens. LEGO Castle revisited classic factions such as Crusaders and Dragon Masters, reconnecting with its medieval roots while bridging into modern set design.