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.
1994 LEGO Sets
In 1994, LEGO expanded global production with the opening of LEGO Mexico, addressing rising worldwide demand. Space introduced two contrasting subthemes: Unitron, featuring monorail transport and exploration craft, and Spyrius, focused on espionage with red-and-black robots and ships. Pirates evolved through the Islanders subtheme, adding new tropical storytelling. The introduction of pink elements expanded LEGO’s color palette and hinted at future inclusivity efforts. These creative and logistical shifts helped define LEGO’s mid-1990s transition toward greater diversity in design and play.