We had a lot more freedom as kids when I was one as well. My parents really had no idea where I was until dinnertime most days and that was fine. We did a little bit of innocent vandalism such as throwing mud on things but never destruction of property and certainly not endangering the lives of others. I loved putting pennies on the tracks and it was a real eye opener about how heavy those cars actually are. I'm still amazed that a single engine can pull all of those and don't understand how it is physically possible. That's something for me to look up today a guess.
Given how much those things weigh it must have been one hell of a piece of heavy equipment to pick them back up!