Last February, exactly one year ago, my children spent three and a half hours by themselves on an Amtrak train ride from New Haven, Conn., to Philadelphia. It was a perfectly functional day that all of us remember fondly -- the kind that makes you bless public amenities like train service. I was happy because I got to drop the kids off at the train station instead of spending an entire day making the trek to their grandparents’ with them and back. Eli and Simon, who at the time were 11 and 8, were pleased that they successfully fended for themselves (and ate all the pizza they wanted along the way). And my parents were of course glad to pick up the children from the nice attendant whose job it was to deliver them, and delighted to spend the long weekend with them.