And conversely, when did you 'outgrow' it and were diverted by other interests?
Better include when your interest in trains returned too!
Have noticed many different scearios that we've all experienced. The thread about and the photo of "Shorpy" mentions him 'about to discover girls' is a common one.
I remember an article in one of our magazines about a man who received his first Lionel at age 9 and was made to sit on the couch and watch his dad and uncle run the trains for him - NINE years old and he had to sit on the couch??? From his countenance in the (present day) photo it appeared that the incident may have caused permanent emotional damage!