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.
1974 LEGO Sets
1974 saw the Universal Building Set broaden parts variety and color, while large ‘Family’ (maxi) figures and the Homemaker line brought interiors and furniture to the forefront. Early mechanical elements began laying groundwork for later Expert Builder/Technic. Trains continued to evolve on 12V in Europe, refining the system ahead of the 1980s expansion.