I was given my first Lego train set #127 in 1974, my mother said I played with it non-stop for 2 weeks. http://brickset.com/sets/theme-Trains/subtheme-4-5-12-V
In those days, the Lego train set came already made in the box and my mum was terrified when I started taking it to pieces to make something new without any instructions.