The floor rules here were "cast steam" which you can hardly break; or "low cost" if plastic.
Gramps layout rules were act right or you can't man the throttle next time.
I only got banned once...tramatic, but eye opening.
"These are MY trains, go crash YOUR trains into hot wheels"...and the basement went dark.
The more responsible I was, the better trains I was allowed to handle. I railed and ran Black Jack GG-1 once, no other Grandkids ever got to run one, let alone the one from the top shelf.
For many, it is a progression from unbridled excitement and activity, to sitting around quietly watching night trains slowly rolling by, which is why I slowed mine down.......sometimes. 
That speed limiter is like modern train insurance though.
There are a few old threads on the subject too if you search around.
