...so that Jack could do this:
...without having to worry about this:
Sam was really good about not touching the train, but any time that Jack lays on the ground, Sam can't resist climbing all over him! Jack loves it, but sometimes it was a little frustrating for him not to ever be able to give his full attention to the clickety-clacks so we took pity on him. It had the added bonus, too, of giving them a new game to play! They loved to peek and poke at each other through/over the gate!
And this is what Jack thought of the gate: