4512V covers the LEGO trains of the 4.5 V and 12 V systems from the 1970s and 1980s. The 4.5 V trains ran on batteries carried in a wagon or tender, while the 12 V trains drew power from conductor rails laid between the running rails, fed by a transformer with a speed control. Until 1980 the track was blue, which gave these years the name of the Blue Era.
1976 LEGO Sets
In 1976, town-focused play deepened with emergency and civic sets—police, fire, and services—while the train range saw continued refinement of 12V equipment and rolling stock. Basic Building Sets emphasized open-ended creativity. Fully fledged Space and Castle themes would follow in 1978.