In 1972 LEGO released the 4.5V and 12V train sets as part of the Blue Era which was named because of the rail color. These train sets used additional conductor rails mounted between the standard 4.5V rails and 12V motors contained in the same housings as the 4.5V motors, but with additional metal contacts attached to the bottom of the housings.
1983 LEGO Sets
In 1983, LEGO released the LEGO Castle theme, which transported builders to medieval times with knights, castles, and dragons. This theme's emergence allowed children to delve into historical and fantasy-based narratives, building and role-playing epic battles and legendary tales. Additionally, the Duplo line, aimed at younger children, was further enriched.