One of my wife’s high school classmates has a daughter who handlays track with dad…
One of my club’s members lost a N scale GG1 to his son ripping the wheels off at the age of 4 or so. It was repairable, but he now plays with Lionel trains.
The kid has a lot to do with it. If they are the type that likes to disassemble things to their smallest components, then maybe HO not quite right at 5.
I was the take things apart type person. I disassembled every HO locomotive that I owned until it no longer worked, not that the pancake motors and vertical truck mounted motors worked all that well.
I particularly remember being really annoyed that the BRIO trains magnets where polarized, so you could not do certain switching moves with them…(might have held onto those a bit too long), I think my youngest cousin has them now.
I got my (at the time) 7 year old cousin an Ogauge RTR set (I remember being somewhat distraught that the only trainsets available from MTH were PRR sets, it pained me to purchase PRR for him, but family won out over petty railroad differnces) (NYC fan).