
The LEGO 4.5V train theme ran from 1966 until 1971 and contained 39 sets in all. The 4.5V trains used to be the voltage standard for the first electric LEGO components where the power came from a battery box with 3x 1.5V batteries.
1968 LEGO Sets
In 1968, LEGO introduced a new box design, featuring "idea book"-style images on both the front and back, while the now-familiar LEGO logo was moved to the side of the packaging. This design was similar to the approach Samsonite had used for several years. As LEGO continued its transition to a larger and more standardized scale, many Basic sets were updated to reflect this modern scale, while older sets with smaller scales were phased out.